Prevalence of coronary blood flow reserve abnormalities among patients with nonobstructive coronary artery disease and chest pain

BACKGROUND: Very little is known about the mechanisms underlying adverse reactions to radiocontrast medium. On the basis of the clinical features of the adverse reactions, it has generally been considered that an IgE-dependent mechanism is not involved in these adverse reactions, and only a few studies have demonstrated the presence of IgE antibody to radiocontrast medium in patient sera. METHODS: We assayed for IgE antibody to ioxaglic acid (Hexabrix), a representative radiocontrast medium, in the sera of patients who had developed adverse reactions to ioxaglic acid. A conjugate was prepared by coupling succinyl ioxaglic acid to human serum albumin. Enzyme immunoassay and radioimmunoassay for the detection of IgE antibody to ioxaglic acid in patient sera were constructed by physical adsorption or by covalent coupling of the conjugate on solid supports. RESULTS: When the radioactivity or the absorbance exceeding the mean plus 3 SD for normal healthy subjects was regarded as positive, IgE antibody was detected in the sera of 47.1% of the patients who had a past history of adverse reactions to ioxaglic acid and 16.2% of those who had experienced adverse reactions to ioxaglic acid within 24 h before the blood collection, although the IgE antibody levels were low. On the other hand, IgE antibody to ioxaglic acid was not detected in the sera of patients with no history of adverse reactions to ioxaglic acid. Inhibition experiments revealed the presence of IgE antibody specific to ioxaglic acid in the serum defined as positive for IgE antibody to ioxaglic acid. The presence of IgE antibody to ioxaglic acid did not always correlate with the activation of mast cells due to the occurrence of adverse reactions to ioxaglic acid. CONCLUSIONS: A small amount of IgE antibody to ioxaglic acid was detected in the sera of some patients with a history of adverse reactions to ioxaglic acid, and these adverse reactions may be partly explained by the presence of IgE antibody in the serum of at least some patients.     

Regional myocardial blood flow during hyperemia induced by contrast agent in patients with coronary artery disease

Regional myocardial specific blood flow (regional specific flow) was measured at rest and during contrast hyperemia after the intracoronary injection of xenon-133. The changes in regional specific flow were transient, resulting in some compromise in one of the underlying restraints of the inert gas washout method, namely, the presence of a steady state. Therefore, to determine the clinical utility of this technique, regional specific flow values obtained with this method were correlated with the presence and severity of coronary artery disease as assessed from the coronary arteriogram and left ventriculogram. Regional specific flow during contrast hyperemia was 186+/- 11 (mean +/- 1 standard error of the mean) ml/min per 100 g in control patients and 115+/-5 in patients with coronary artery disease. There was an inverse relation between regional specific flow during contrast hyperemia and the percent coronary stenosis when the stenosis was 40 percent or greater (r = 0.70, P less than 0.001). Regional specific flow was significantly less in patients with asynergy (77 +/- 10 ml/min per 100 g) than in patients with normal ventricular function (105 +/- 5) distal to coronary stenoses of greater than 75 percent. Thus regional specific flow measured during contrast hyperemia using the xenon washout technique and the Anger camera differentiated patients with normal coronary arteriograms from those with coronary artery disease. With this technique, good correlation was shown between regional specific flow and the percent coronary stenosis and presence of ventricular wall abnormalities. The information obtained with this method may provide prognostic information concerning suitability for surgical intervention.     

Effects of respiratory alkalosis and acidosis on myocardial blood flow and metabolism in patients with coronary artery disease

BACKGROUND: Variation of the arterial carbon dioxide partial pressure (PaCO2) is not uncommon in anesthetic practice. However, little is known about the myocardial consequences of respiratory alkalosis and acidosis, particularly in patients with coronary artery disease. The aim of the current study was to investigate the effects of variation in PaCO2 on myocardial blood flow (MBF), metabolism, and systemic hemodynamics in patients before elective coronary artery bypass graft surgery. METHODS: In 10 male anesthetized patients, measurements of MBF, myocardial contractility, metabolism, and systemic hemodynamics were made in a randomized sequence at PaCO2 levels of 30, 40, and 50 mmHg, respectively. The MBF was measured using the Kety-Schmidt technique with argon as a tracer. End-diastolic left ventricular pressure and the maximal increase of left ventricular pressure were assessed using a manometer-tipped catheter. RESULTS: The cardiac index significantly changed with varying PaCO2 levels (hypocapnia, - 9%; hypercapnia, 13%). This reaction was associated with inverse changes in systemic vascular resistance index levels. The MBF significantly increased by 15% during hypercapnia, whereas no change was found during hypocapnia. Myocardial oxygen and glucose uptake and the maximal increase of left ventricular pressure were not affected by varying PaCO2 levels. CONCLUSIONS: In anesthetized patients with coronary artery disease, short-term variations in PaCO2 have significant effects on MBF but do not influence global myocardial oxygen and glucose uptake. Changes in systemic hemodynamics associated with respiratory alkalosis and acidosis are caused by changes in systemic vascular resistance rather than by alterations in myocardial contractility.     

Elective stenting of carotid artery stenosis in patients with severe coronary artery disease

AIMS: To evaluate the feasibility and safety of elective carotid stent implantation in patients with carotid stenoses and concomitant coronary artery disease, as an alternative to combined carotid and coronary surgery. METHODS: We treated 50 patients with >70%, stenoses in 53 carotid arteries with balloon angioplasty followed by elective stent implantation. All patients had severe coronary artery disease, and/or mitral insufficiency, aortic stenosis, rhythm disorders or generalized arteriosclerosis. In three patients the opposite carotid artery was occluded; nine patients had bilateral stenoses of which two received stents bilaterally. RESULTS: Fifty-six successful stent implantations (42 Wallstents, eight BeStents, two AVE-Microstents, one Palmaz Schatz stent, three Sito stents) were performed, reducing the baseline percent stenosis from 78 +/- 18%, to 13 +/- 11%. Complications included three transient ischaemic attacks, one minor and one major stroke. Follow-up was available for 46 patients over a mean of 10 months. Three asymptomatic restenoses and one deformation of a BeStent occurred. CONCLUSION: Our preliminary results indicate that carotid artery stenting in patients with concomitant severe coronary artery disease is feasible, safe, and may be an alternative to combined carotid and coronary surgery.     

Assessment of blood flow distal to coronary artery stenoses. Correlations between myocardial positron emission tomography and poststenotic intracoronary Doppler flow reserve

BACKGROUND: Previous studies have correlated quantitative coronary angiographic stenosis severity with positron emission tomography (PET) myocardial perfusion and proximal measurements of intracoronary flow velocities in normal and diseased coronary arteries. The aim of this study was to correlate regional myocardial blood flow (RMBF) derived from [15O]H2O PET with directly measured poststenotic intracoronary Doppler flow velocity data acquired under basal conditions and dipyridamole-induced hyperemia. METHODS AND RESULTS: Eleven consecutive patients 53 +/- 13 years old with ischemic chest pain and isolated proximal left coronary artery stenoses (left anterior descending, 9; left circumflex, 2; mean, 59 +/- 23% diameter stenosis) underwent [15O]H2O myocardial PET and intracoronary Doppler flow velocity studies within 1 week. PET RMBF (mL.g-1.min-1) and myocardial perfusion reserve (MPR) were calculated in poststenotic and normal reference vascular beds. Poststenotic Doppler average peak flow velocities (APV; cm/s) and coronary flow velocity reserve (CFR) were compared with corresponding PET data and quantitative angiographic lesional parameters. PET RMBF and Doppler APV were linearly correlated (r = .60; P < .001), as were poststenotic PET MPR and Doppler CFR (r = .76; P < .0002). Relative coronary flow velocity and MPR ratios between poststenotic and angiographically normal vascular beds were comparably reduced (0.83 +/- 0.25 versus 0.86 +/- 0.21, respectively; P = NS). CONCLUSIONS: Intracoronary Doppler flow velocities acquired distal to isolated left coronary artery stenoses correlated with [15O]H2O PET regional myocardial perfusion and are useful for assessment of the physiological significance of coronary stenoses in humans.     

Noninvasive assessment of significant left anterior descending coronary artery stenosis by coronary flow velocity reserve with transthoracic color Doppler echocardiography

BACKGROUND: Coronary flow reserve has been considered an important diagnostic index of the functional significance of coronary artery stenosis. With Doppler technique, it has been assessed as the ratio of hyperemic to basal coronary flow velocity (coronary flow velocity reserve [CFVR]) by invasive or semiinvasive methods with a Doppler catheter, a Doppler guide wire, and a transesophageal Doppler echocardiographic probe. Recent technological advancement in transthoracic Doppler echocardiography (TTDE) provides measurement of coronary flow velocity in the distal portion of the left anterior descending coronary artery (LAD) and may be useful in the noninvasive CFVR measurement. The purpose of this study was to evaluate the value of CFVR determined by TTDE for the assessment of significant LAD stenosis. METHODS AND RESULTS: We studied 36 patients who underwent coronary angiography for the assessment of coronary artery disease. The study population consisted of 12 patients with significant LAD stenosis (group A) and 24 patients without significant LAD stenosis (group B). With TTDE, coronary flow velocities in the distal LAD were recorded at rest and during hyperemia induced by intravenous infusion of adenosine (0.14 mg x kg(-1) x min(-1)) under the guidance of color Doppler flow mapping. Adequate spectral Doppler recordings of coronary flow in the distal LAD for the assessment of CFVR were obtained in 34 of 36 study patients (94%). The peak and mean diastolic coronary flow velocities at baseline did not differ between groups A and B (23.6+/-10.3 versus 22.9+/-6.6 cm/s and 16.4+/-8.6 versus 14.5+/-4.0 cm/s, respectively). However, the peak and mean coronary flow velocities during hyperemia in group A were significantly smaller than those in group B (35.6+/-16.3 versus 54.2+/-16.3 cm/s and 24.7+/-13.1 versus 37.9+/-13.0 cm/s, respectively; P<.01). There were significant differences in CFVR obtained from peak and mean diastolic velocity between groups A and B (1.5+/-0.2 versus 2.4+/-0.4 and 1.5+/-0.2 versus 2.6+/-0.4, respectively; P<.001). A CFVR from peak diastolic velocity <2.0 had a sensitivity of 92% and a specificity of 82% for the presence of significant LAD stenosis. A CFVR from mean diastolic velocity <2.0 had a sensitivity of 92% and a specificity of 86% for the presence of significant LAD stenosis. CONCLUSIONS: CFVR determined by TTDE is useful in the noninvasive assessment of significant stenotic lesion in the LAD.     

Experimental basis of determining maximum coronary, myocardial, and collateral blood flow by pressure measurements for assessing functional stenosis severity before and after percutaneous transluminal coronary angioplasty

BACKGROUND: Severity of coronary artery stenosis has been defined in terms of geometric dimensions, pressure gradient-flow relations, resistance to flow and coronary flow reserve, or maximum flow capacity after maximum arteriolar vasodilation. A direct relation between coronary pressure and flow, however, may only be presumed if the resistances in the coronary circulation are constant (and minimal) as theoretically is the case during maximum arteriolar vasodilation. In that case, pressure measurements theoretically can be used to predict maximum flow and assess functional stenosis severity. METHODS AND RESULTS: A theoretical model was developed for the different components of the coronary circulation, and a set of equations was derived by which the relative maximum flow or fractional flow reserve in both the stenotic epicardial artery and the myocardial vascular bed and the proportional contribution of coronary arterial and collateral flow to myocardial blood flow are calculated from measurements of arterial, distal coronary, and central venous pressures during maximum arteriolar vasodilation. To test this model, five dogs were acutely instrumented with an epicardial, coronary Doppler flow velocity transducer. Distal coronary pressures were measured by an ultrathin pressure-monitoring guide wire (0.015 in.) with minimal influence on transstenotic pressure gradient. Fractional flow reserve was calculated from the pressure measurements and compared with relative maximum coronary artery flow measured directly by the Doppler flowmeter at three different levels of arterial pressure for each of 12 different severities of stenosis at each pressure level. Relative maximum blood flow through the stenotic artery (Qs) measured directly by the Doppler flowmeter showed an excellent correlation with the pressure-derived values of Qs (r = 0.98 +/- 0.01, intercept = 0.02 +/- 0.03, slope = 0.98 +/- 0.04), of the relative maximum myocardial flow (r = 0.98 +/- 0.02, intercept = 0.26 +/- 0.07, slope = 0.73 +/- 0.08), and of the collateral blood flow (r = 0.96 +/- 0.04, intercept = 0.24 +/- 0.07, slope = -0.24 +/- 0.06). Moreover, the theoretically predicted constant relation between mean arterial pressure and coronary wedge pressure, both corrected for venous pressure, was confirmed experimentally (r = 0.97 +/- 0.03, intercept = 9.5 +/- 13.3, slope = 4.4 +/- 1.2). CONCLUSIONS: These results provide the experimental basis for determining relative maximum flow or fractional flow reserve of both the epicardial coronary artery and the myocardium, including collateral flow, from pressure measurements during maximum arteriolar vasodilation. With a suitable guide wire for reliably measuring distal coronary pressure clinically, this method may have potential applications during percutaneous transluminal coronary angioplasty for assessing changes in the functional severity of coronary artery stenoses and for estimating collateral flow achievable during occlusion of the coronary artery.     

Effects of ergotamine on myocardial blood flow in migraineurs without evidence of atherosclerotic coronary artery disease

The effects of intravenous ergotamine (0.25 mg) on basal and hyperemic (dipyridamole) myocardial blood flow (MBF), measured with positron emission tomography and H2(15)O, were assessed in 15 migraineurs in a double-blind, randomized, placebo controlled, crossover study. Ergotamine produced a 27% reduction in hyperemic MBF (2.62 +/- 0.11 vs 3.72 +/- 1.05 ml x min(-1) x g(-1); p <0.05), a 31% reduction in the coronary vasodilator reserve (1.81 +/- 0.50 vs 2.71 +/- 1.15; p <0.01), and a 55% increase in minimal coronary resistance (42.2 +/- 15 vs 26.7 +/- 8 mm Hg x min x ml(-1) x g(-1); p <0.001), suggesting vasoconstriction of the coronary microcirculation.     

Variations in normal coronary vasodilatory reserve stratified by artery, gender, heart transplantation and coronary artery disease

OBJECTIVES: The purpose of the study was to assess the spectrum of coronary vasodilatory reserve values in patients with angiographically normal arteries who had atypical chest pain syndromes or remote coronary artery disease or were heart transplant recipients. BACKGROUND: The measurement of post-stenotic coronary vasodilatory reserve, now possible in a large number of patients in the cardiac catheterization laboratory, is increasingly used for decision making. Controversy exists regarding the range of normal values obtained in angiographically normal coronary arteries in patients with different clinical presentations. METHODS: Quantitative coronary arteriography was performed in 214 patients classified into three groups: 85 patients with chest pain syndromes and angiographically normal arteries (group 1); 21 patients with one normal vessel and at least one vessel with > 50% diameter lumen narrowing (group 2); and 108 heart transplant recipients (group 3). Coronary vasodilatory reserve (the ratio of maximal to basal average coronary flow velocity) was measured in 416 arteries using a 0.018-in. (0.04 cm) Doppler-tipped angioplasty guide wire. Intracoronary adenosine (8 to 18 micrograms) was used to produce maximal hyperemia. RESULTS: Coronary vasodilatory reserve was higher in angiographically normal arteries in patients with chest pain syndromes (group 1:2.80 +/- 0.6 [group mean +/- SD]) than in normal vessels in patients with remote coronary artery disease (group 2: 2.5 +/- 0.95, p = 0.04); both values were significantly higher than those in the post-stenotic segment of the diseased artery (1.8 +/- 0.6, p < 0.007). Coronary vasodilatory reserve in transplant recipients (group 3) was higher than that in the other groups (3.1 +/- 0.9, p < 0.05 vs. groups 1 and 2) as a group and for individual arteries. When stratified by vessel, coronary vasodilatory reserve was similar among the left anterior descending, left circumflex and right coronary arteries. There were no differences between coronary vasodilatory reserve values on the basis of gender for patients with coronary artery disease and transplant recipients. In group 1 (chest pain), there was a trend toward higher coronary vasodilatory reserve in men than in women (2.9 +/- 0.6 vs 2.7 +/- 0.6, p = 0.07). CONCLUSIONS: These findings identify a normal reference range for studies assessing the coronary circulation and post-stenotic coronary vasodilatory reserve in patients with and without coronary artery disease encountered in the cardiac catheterization laboratory.     

Decreased baroreflex sensitivity in patients with stable coronary artery disease is correlated with the severity of coronary narrowing

Although studies have shown that arterial baroreflex sensitivity (BRS) is decreased in patients with acute myocardial infarction, BRS changes in patients with stable coronary artery disease (CAD) have not been studied extensively. We assessed BRS by the phenylephrine method in 55 normotensive and nondiabetic patients with chronic effort angina, old myocardial infarction, or both. The control group consisted of 24 age-matched patients without coronary lesions. To identify factors that determine BRS in stable CAD, we performed multivariate analysis using age, sex, left ventricular ejection fraction, pulmonary artery wedge pressure, resting systolic blood pressure, resting heart rate, the number of stenotic coronary arteries, history of myocardial infarction, and the presence or absence of angina pectoris as variables. BRS was significantly lower in patients with CAD than in control subjects (5.9 +/- 2.9 vs 6.9 +/- 2.4 ms/mm Hg, p < 0.05). In patients with CAD, BRS was inversely correlated with age, the resting heart rate, and the number of stenotic coronary vessels (p < 0.001, p < 0.005, and p < 0.005, respectively), but was independent of other clinical parameters, including the history of myocardial infarction. In control subjects, BRS was significantly correlated only with age. These results indicate that BRS is decreased in patients with stable CAD, and this decrease is correlated with the extent and severity of coronary narrowing.     

Influence of age and hemodynamics on myocardial blood flow and flow reserve

Colostrum from French-Alpine and Anglo-Nubian goats and Holstein cows was collected and analyzed for both total and FFA of 12 and fewer carbon atoms. Short-chain VFA were separated from long-chain fatty acids using simultaneous distillation extraction. The n-butyl esters of fatty acids were quantified by gas chromatography, and their identity was confirmed by gas chromatography-mass spectrometry. The concentration of decanoic acid was 33 and 83% less in Holstein colostrum than in colostrum from Alpine and Nubian goats, respectively. Colostrum from Nubian goats had twice as much decanoic acid as colostrum from Alpine goats. The FFA in colostrum that differed between species but not between goat breeds were octanoic and decanoic acids. These respective fatty acids were approximately two and three times greater in colostrum from goats than in colostrum from Holsteins. The quantity of decanoic acid was different between goat breeds and between animal species. The ratio of total fatty acid concentration to free-state concentration for hexanoic acid appeared to be useful for differentiating between Nubian and Alpine goat colostrum as well as between Nubian and Holstein colostrums.     

Comparison of exercise electrocardiography and dobutamine echocardiography with invasively assessed myocardial fractional flow reserve in evaluation of severity of coronary arterial narrowing

This study compares side-by-side exercise electrocardiography and dobutamine echocardiography with an invasively assessed index of myocardial flow (pressure-derived myocardial fractional flow reserve). The data show that ST-segment depression > or = 0.1 mV and the occurrence of new wall motion abnormalities during dobutamine infusion reflect a similar impairment of myocardial blood flow.     

Impact of impaired coronary flow reserve and insulin resistance on myocardial energy metabolism in patients with syndrome X

To evaluate the role of a decreased coronary flow reserve in the genesis of angina pectoris in patients with syndrome X, we studied myocardial hemodynamics and metabolism at rest, during pace stress, and in the recovery period after pacing in 18 consecutive patients with syndrome X and in 10 control subjects. By means of positron emission tomography or the intracoronary flow-wire method, patients were subclassified as having microvascular angina (MA, n = 8) when coronary flow reserve was reduced (<2.5) or no microvascular angina (non-MA, n = 10) when coronary flow reserve was preserved (> or =2.5). At rest, coronary sinus blood flow was increased in MA patients. During pace stress, coronary sinus blood flow increased by 39 +/- 6% in MA patients versus 67 +/- 12% in non-MA patients and 69 +/- 7% in controls (p <0.05). Patients with non-MA revealed fasting hyperinsulinemia, increased arterial concentration of free fatty acids, and a similar tendency for beta-hydroxybutyrate. Oxygen extraction and carbon dioxide release did not differ between groups. Net myocardial lactate release was not observed in any patient during pace stress and myocardial energy metabolism was preserved in all patients with syndrome X. During pacing, myocardial uptake of free fatty acids and beta-hydroxybutyrate was increased in non-MA patients. Myocardial uptake of free fatty acids correlated positively and myocardial glucose and lactate uptake correlated inversely with arterial concentrations of free fatty acids in all subjects. Metabolic evidence of myocardial ischemia is uncommon in patients with syndrome X, irrespective of a globally reduced coronary flow reserve. Although patients with syndrome X can be subclassified according to presence of a microvascular or a metabolic disorder, angina pectoris and ST-segment depressions coexist with a preserved global myocardial energy efficiency in all patients.     

Hyperinsulinism in patients with coronary artery disease

AIM: To assess the clinical impact of hyperinsulinism and major coronary risk factors in patients with angiographically documented or excluded coronary artery disease (CAD), a clinical study was carried out in 268 men admitted for left heart catheterization. METHODS: Fasting immunoreactive insulin (IRI) levels were correlated to all major cardiovascular risk factors and to the presence and degree of CAD. RESULTS: IRI levels were correlated significantly with the degree of CAD (one-vessel disease: mean IRI 9.45 microU/ml +/- 0.43 SEM; two-vessel disease: mean IRI 10.4 microU/ml +/- 0.71 SEM; three-vessel disease: mean IRI 11.88 microU/ml +/- 0.98 SEM) and inversely to the high-density lipoprotein level (P < 0.05). In patients with arterial hypertension, IRI levels were elevated, without a significant difference between those with and those without CAD, whereas the IRI levels of non-hypertensive men with CAD (n = 81; mean IRI 9.85 microU/ml +/- 0.51 SEM) differed significantly (P < 0.05) from those of non-hypertensive men without CAD (n = 59; mean IRI 7.76 microU/ml +/- 0.43 SEM). IRI levels were significantly higher (P < 0.05) in obese patients (n = 65; mean IRI 11.68 microU/ml +/- 0.70 SEM versus n = 203; mean IRI 9.32 microU/ml +/- 0.34 SEM), in patients with elevated triglycerides (n = 58 mean IRI 11.59 microU/ml +/- 0.81 SEM versus n = 210; mean IRI 9.42 microU/ml +/- 0.33 SEM), and in patients with lowered HDL cholesterol (n = 178; mean IRI 11.06 microU/ml +/- 0.63 SEM versus n = 90; mean IRI 9.29 microU/ml +/- 0.34 SEM). Diabetic patients on angiotensin converting enzyme inhibitor therapy (n = 11; mean IRI 7.91 microU/ml +/- 0.91 SEM) had significantly (P < 0.05) lower IRI levels than those not treated with ACE inhibitors (n = 25; mean IRI 12.96 microU/ml +/- 1.47 SEM). IRI levels exceeding 8 microU/ml were associated with a 1.98-fold risk for CAD compared with IRI levels below 8 microU/ml. Stepwise logistic regression showed that insulin was an independent determinant of CAD. CONCLUSION: Knowledge of the fasting insulin level is an important contribution to the identification of patients with, or at risk of, CAD.     

Modifications of the coronary blood flow and of myocardial lactate metabolism due to pacing in coronary disease

The variation of coronary sinus blood flow during pacing-induced tachycardia shows no direct correlation with the number of affected coronary arteries. As a functional test, total coronary blood flow is a parameter with low sensitivity in characterizing patients with coronary artery disease and thus appears unsuitable in the selection of patients for medical or surgical treatment. The thermodilution technique remains useful for the assessment of the effects of new drugs on the heart, for the evaluation of a therapeutic intervention, and for the selective measurement of regional myocardial perfusion in the anterior interventricular vein.     

Evaluation of coronary flow velocity dynamics and flow reserve in patients with Kawasaki disease by means of a Doppler guide wire

OBJECTIVES: To assess the pathophysiologic effects of the coronary sequelae of Kawasaki disease on coronary hemodynamic variables, we regionally evaluated the flow velocity dynamics and flow reserve in coronary vessels with lesions using an intracoronary Doppler flow guide wire. BACKGROUND: The pathophysiologic effects of the coronary sequelae of Kawasaki disease on coronary hemodynamic variables have not been completely clarified, and we previously reported some discrepancies between coronary angiographic findings and exercise stress tests in Kawasaki disease. METHODS: Doppler phasic coronary flow velocity was determined using an 0.018-in. (0.046-cm) intracoronary Doppler flow guide wire at rest and during the adenosine triphosphate-induced hyperemic response in 95 patients (75 male, 20 female, mean age 9.8+/-6.2 years) with Kawasaki disease. RESULTS: In 25 patients with coronary aneurysms in 29 vessels, the average peak velocity and diastolic to systolic velocity ratio were significantly (p < 0.05) decreased in the moderate-sized and large-sized aneurysms. Significantly lower values in coronary flow reserve (CFR) were noted in 3 of 10 vessels with moderate aneurysms and in 4 of 7 vessels with large aneurysms. A significant positive correlation (y = 0.53x + 14.6, r2 = 0.91) was observed between the percent diameter stenosis evaluated by angiography and that calculated from the flow velocity measurement. However, the percent diameter stenosis calculated from the flow velocity measurement was underestimated compared with that determined by angiography in the stenotic lesions of intermediate severity. A reduced CFR was noted in five of seven vessels with intermediate stenosis ranging from 50% to 75%, and also in three vessels with mild stenosis ranging from 30% to 40%. A reduced CFR was also observed in six of the eight angiographically normal vessels associated with the area of reduced perfusion on exercise thallium-201 myocardial scintigraphy. CONCLUSIONS: Abnormalities in flow dynamics and a reduction in flow reserve were revealed in coronary aneurysms of intermediate to large size and in stenotic lesions, even of mild to intermediate severity, in patients with Kawasaki disease. Abnormalities in the coronary microcirculation, as well as epicardial lesions, contribute to the pathophysiologic responses in Kawasaki disease.     

Coronary flow reserve in the contralateral artery increases after successful coronary angioplasty in patients with spontaneously visible collateral vessels

Due to the large variability in the reported contribution of bladder dysfunction to postprostatectomy incontinence and the impact this dysfunction may have on the outcome of selected treatment, we retrospectively reviewed the videourodynamic findings of bladder and sphincteric function in patients with postprostatectomy incontinence. The contributions of bladder and sphincteric causes of incontinence are determined. Ninety-two patients had multichannel videourdynamic testing performed as part of a comprehensive evaluation for incontinence at least 1 year after prostatectomy. Using a 6-French double-lumen catheter in the bladder and a 10-French catheter in the rectum, all pressures were recorded continuously while in the upright position. Valsalva leak point pressures (VLPP) were measured in the absence of a bladder contraction at a 150-ml volume and at 50-ml increments thereafter until maximum functional capacity was reached. Bladder compliance and bladder capacity were determined and the presence of detrusor instability (DI) was documented. Sixty-five patients (71%) presented after radical prostatectomy (RP) and 27 patients (29%) after transurethral resection of the prostate (TURP). The predominant urodynamic finding was sphincteric incompetence as VLPP were obtained in 85 patients (92%) and ranged from 12 to 120 cm water. DI was a common finding, occurring in 34 patients (37%), and classified as follows: a) phasic instability in 22/34, b) tonic instability in 3/34, and c) mixed phasic and tonic instability in 9/34. However, we found DI to be the sole cause of incontinence in only 3/92 patients (3.3%). There was no statistically significant difference in the incidence of sphincteric incompetence after RP or TURP; however, TURP patients had a higher incidence of DI, which was statistically significant (P=0.019). There was no correlation of incontinence severity and VLPP when comparing preoperative pad usage to VLPP < or =70 or > or =71 cm water. Although bladder dysfunction may be contributing problem in patients with postprostatectomy incontinence, it is rarely the only mechanism for this disorder. VLPP does not correlate with incontinence severity. Although sphincteric incompetence is the most common mechanism contributing to incontinence after prostatectomy, bladder dysfunction may coexist or be an isolated cause of postprostatectomy incontinence. Therefore, urodynamic studies are important to illustrate the exact cause(s) of incontinence in each individual patient after prostatectomy.     

Normal coronary flow reserve in patients with mitral valve prolapse, a positive exercise test and normal coronary arteries

We studied 12 patients (eight females and four males), ages 30-46 years, with echocardiographically documented mitral valve prolapse and clinical suspicion of coronary artery disease, based on a history of chest pain (five patients), angina-like pain (three patients), a positive exercise stress electrocardiogram (12 patients) and a focally positive thallium-201 stress perfusion scan (three patients), who were referred for cardiac catheterization and found to have normal coronary arteries. Ten patients without evidence of heart disease served as controls. In all mitral valve prolapse patients, coronary flow velocity reserve was determined successively in the left anterior descending, left circumflex and right coronary arteries as the ratio of the maximum (after intracoronary papaverine) to the resting mean coronary flow velocity. Coronary flow reserve values were fairly similar in the mitral valve prolapse and control patients; all 12 mitral valve prolapse patients had normal coronary flow reserve ( > or = 3.5) in all three coronary arteries with no significant differences among the arteries tested. Mean values +/- 1 standard deviation of the coronary flow reserve (mitral valve prolapse vs control patients) were 4.7 +/- 0.5 vs 4.6 +/- 0.6 for the left anterior descending, 4.6 +/- 0.4 vs 4.6 +/- 0.3 for the left circumflex and 4.5 +/- 0.4 vs 4.4 +/- 0.5 for the right coronary artery (all P = non-significant). The subsets of mitral valve prolapse patients with different clinical "ischaemic' manifestations were similar in terms of the calculated coronary flow reserve in all three major epicardial coronary arteries. In conclusion, this study demonstrated that an inadequate regional coronary flow reserve does not account for the clinical manifestations of myocardial ischaemia and positive exercise tests in patients with mitral valve prolapse and normal coronary arteries.     

Exertional syncope in a patient with aortic stenosis and right coronary artery disease

A female with advanced aortic valvular stenosis and moderate right coronary artery disease experienced an exertional syncope during 24-h ambulatory electrocardiographic monitoring. A progressive bradycardia with 90-s sinus node arrest (cardio-inhibitory response) and premonitory angina pectoris with significant ST segment changes were demonstrated. Our report supports the concept of a neurocardiogenic (vasovagal) mechanism of exertional syncope in patients with aortic stenosis. The predominant left ventricular inferior-wall myocardial ischaemia in our patient might be an additional stimulus to left ventricular mechanoreceptors, resulting in a profound cardio-inhibitory response.     

Evaluation of functional importance of coronary artery stenosis by intracoronary Doppler blood flow velocity measurement

Intracoronary doppler blood flow velocity measurements supply important information for clinical decision making during angioplasty, especially with regard to stenoses of ambiguous severity. In the presence of an intermediate stenosis of unknown physiological impact (40-60%), determination of normal flow parameters (coronary flow reserve: CFR, diastolic to systolic velocity ratio: DSVR and proximal to distal velocity ratio: P/D) will make deferment of treatment acceptable. Post-angioplasty success can be based on restoral of normal flowparameters. The inability to achieve normal CFR immediately after angioplasty does not indicate an unsuccessful procedure, it remains to be shown whether a lack of normalization of DSVR and/or P/D does so. Continuous post-lesional flow monitoring can show and quantify the existence of collateral flow.