Complete occlusion of the left main coronary artery and the importance of coronary collateral circulation

Study of four patients who survived complete occlusion of the left main coronary artery forms the basis of conclusions concerning the functional significance of coronary collateral circulation. Each of these patients had prominent collateral circulation from the right coronary artery. Global left ventricular function was maintained to the extent that congestive heart failure did not occur; the biplane ejection fraction was normal in the two patients where measurement was possible. The peak rate of systolic wall thickening by roentgen videometry in anterior left ventricular segments was normal in one patient and mild to moderately depressed in another. Experience with the patients described herein indicates that coronary collateral flow can provide critically needed circulatory support for the patient with coronary artery disease.     

Coronary collateral blood-flow velocity improves with repeated coronary occlusions during angioplasty in patients with coronary artery disease and systemic hypertension

The heterogeneity of schizophrenia has led to a multitude of diagnostic criteria systems. Thus, the best strategy for schizophrenia research might be the use of several diagnostic systems simultaneously. This polydiagnostic approach can be associated with isolating subtypes of symptoms or patients. In this way, the authors present several approaches such as, first, dimensional approaches, second, cluster analyses, and third the selection of a very homogeneous subtype with standardized criteria. One homogeneous subtype can be represented by deficit schizophrenia according to Carpenter as defined by the Schedule of Deficit Syndrome.     

Immediate angioplasty results of total coronary artery occlusion in Thai population

Attempted angioplasty of totally occluded vessels may be done. However, a lower success rate is expected compared to those with subtotal occlusion. The complication rate is comparable to that of partial occlusion in experienced hands.     

Is percutaneous transluminal coronary angioplasty in chronic total coronary occlusion justified? Long term results in a series of 201 patients

Percutaneous transluminal coronary angioplasty of chronic total coronary occlusions has a low primary success rate and is associated with a high percentage of restenosis. The aim of this retrospective study was to assess the long-term benefits of these procedures. In a series of 201 patients with 203 chronic total occlusions, the technical success rate was 51%, the clinical success rate was 46% with 3% of major complications. The only factor associated with a favourable outcome was the presumed duration of the occlusion. The clinical follow-up period was established at 6 years. The result of the initial procedure was used to establish two groups of patients: group I, clinical success, and group II, clinical failure. Patients in group I had a probability of survival greater than that of those in group II (97 vs 92%; p < 0.05); survival without coronary bypass surgery was also significantly better (89 vs 74%; p < 0.003). On the other hand, the probability without angioplasty was less in group I (70 vs 77%; p < 0.01), the result of a high restenosis rate (48%). A Cox analysis identified clinical success of angioplasty as a good prognostic factor for survival. Moreover, the clinical status at long-term was significantly better in patients in group I. These results indicate that in patients with chronic total coronary occlusions, the success of angioplasty has a favourable effect on long-term outcome both in terms of survival and in quality of life. They must be interpreted in the light of the limitations inherent in a retrospective study and should be confirmed by prospective trials.     

The role of the coronary collateral circulation in limiting myocardial ischemia and infarct size

The role of coronary collateral circulation in limiting ischemia and infarction has been studied prospectively. Transient occlusion of a coronary artery angioplasty has provided evidence that collateral circulation decreases wall motion abnormalities, ST segment changes, and lactate production. Patients who have collateral flow also have a better outcome after coronary artery dissection and acute closure than patients without collateral flow. Collateral circulation also limits infarct size during acute myocardial infarction with and without thrombolysis. Although collateral flow may decrease coronary artery bypass graft patency in certain subgroups of patients, the perioperative infarct rate and mortality is decreased. Growth factors have been identified that increase the development collateral circulation and may improve ventricular function in the setting of myocardial infarction.     

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.     

Pathophysiology of coronary collateral circulation in the human

The functional relevance of coronary collaterals in humans has yet to be fully explored. Several studies demonstrated a protective role of collaterals in patients with coronary artery disease. On the other hand, negative aspects of well-developed coronary collaterals have been reported, e.g. a higher rate of restenosis following coronary angioplasty, or a redistribution of blood via collaterals away from the myocardial area in need towards normally perfused areas (coronary steal). In the past, the coronary collateral circulation has been assessed only qualitatively, using visual angiographic or nuclear imaging methods. With the recent advent of intracoronary Doppler and pressure-transducers, quantitative assessment of functional parameters of the coronary circulation has become feasible. This article reviews ongoing research in the field of coronary collaterals in humans, concerning their exact determination, the positive and negative aspects of their structure as well as their functional aspects.     

Determinants of collateral development in a canine model with repeated coronary occlusion

It is now accepted that repetitive 2-min coronary occlusion can develop collateral vessels to the area perfused by the occluded coronary artery. However, which factors influence collateral development has yet to be fully elucidated. The goal of the present study was to identify the determinants of the rate of coronary collateral development in dogs undergoing repeated coronary occlusion. The study was conducted in 19 conscious dogs instrumented for measurements of a subendocardial segment length in the area perfused by the left circumflex coronary artery (LCCA), LCCA flow, and left ventricular pressure. An externally inflatable pneumatic occluder was placed around the LCCA. After the recovery from surgery, 2-min LCCA occlusions were conducted eight times daily. Following 141 +/- 61 (SD) LCCA occlusions (20 +/- 7 days), an LCCA occlusion produced no reduction in segment shortening and negligible reactive hyperemia. The total number of LCCA occlusions needed for adequate collateral development (the rate of collateralization) correlated well with the severity of myocardial ischemia during the first occlusion, which was determined mainly by the extent of postsurgical initial collateral circulation. On the other hand, the response to the ischemic stimulus in the later stage of collateral development was independent of the extent of development of the initial postsurgical collaterals. It is concluded that the overall rate of collateral development is slower in dogs with initially poorer collaterals; however, the response of each dog to the ischemic stimulus in the later stage of collateral development was similar among dogs regardless of the extent of the initial collaterals.     

Influence of tachycardia on regional myocardial flow in chronic experimental coronary occlusion

The influences of tachycardia on regional myocardial flow was studied in normal dogs and in dogs with chronic coronary artery occlusions. Coronary vasodilation was induced by coronary occlusion and subsequent release, i.e. by reactive hyperemia. Local myocardial blood flow was determined with the tracer microspheres technique. In normal hearts atrial pacing produced a slight but significant increase in coronary resistance in the subendocardial layers of the left ventricle. The coronary resistance of the subepicardium remained unaffected. In the right ventricle atrial pacing had no influence on the resistance to flow. In hearts with multiple coronary occlusions tachycardia-induced changes of coronary resistance were more pronounced. In the collateral dependent subendocardium coronary resistance increased from 0.4-2.2 resistance units when the heart rate was raised to 200 beats/min. Perfusion of the right ventricular myocardium became also rate-dependent when the right coronary artery was chronically occluded. We conclude that regional perfusion dependes upon the relationship between the effective perfusion pressure, which is reduced in chronic coronary occlusion, and the integral of effective tissue pressure, which is increased with tachycardia. The results cannot be explained by assuming excessive O2-demand but rather by a rate-induced lowered O2-supply.     

Excimer laser angioplasty versus balloon angioplasty in functional and total coronary occlusions

Registries of excimer laser coronary angioplasty have reported good results in the treatment of complex coronary artery disease, including total or subtotal coronary occlusions. One hundred three patients (103 lesions) with a functional or total coronary occlusion were included in a randomized trial (Amsterdam-Rotterdam [AMRO] trial, total of 308 patients), 49 patients were allocated to laser angioplasty and 54 patients to balloon angioplasty. The primary clinical end points were death, myocardial infarction, coronary bypass surgery, or repeated coronary angioplasty of the randomized segment during a 6-month follow-up period. The primary angiographic end point was the minimal lumen diameter at follow-up in relation to the baseline value (net gain), as determined by an automated contour-detection algorithm. Laser angioplasty was followed by balloon angioplasty in all procedures. The angiographic success rate was 65% in patients treated with excimer laser-assisted balloon angioplasty compared with 61% in patients treated with balloon angioplasty alone. No deaths occurred. There were no significant differences between the laser angioplasty group and the balloon angioplasty group in the incidence of myocardial infarctions (1 patient vs 3, respectively, p = 0.36), coronary bypass surgery (4 patients vs 2, respectively, p = 0.34), repeat angioplasty (10 patients vs 8, respectively, p = 0.46) or primary clinical end point (15 patients vs 12, respectively, p = 0.34). The net gain in minimal lumen diameter and restenosis rate (>50% diameter stenosis at follow-up) were 0.81 +/- 0.74 mm and 66.7%, respectively, in patients treated with laser angioplasty compared with 1.04 +/- 0.68 mm and 48.5%, respectively, in patients treated with balloon angioplasty (p = 0.59 and p = 0.15, respectively). Excimer laser-assisted balloon angioplasty demonstrated no benefit over balloon angioplasty with respect to initial and long-term clinical and angiographic outcome in the treatment of patients with functional or total coronary occlusions of >10 mm in length.     

Heterogeneity of prognosis in patient subsets treated by primary coronary angioplasty during acute myocardial infarction

Among 377 patients consecutively treated with primary coronary angioplasty for acute myocardial infarction, in-hospital mortality was higher in patients ineligible than in patients eligible for thrombolysis (14.4% vs 7.8%, p <0.05). It remained dismal (75.9%) in patients with cardiogenic shock, but was similar in lytic-eligible patients and in those who were ineligible because of an increased bleeding risk (7.8% vs 7.2%, p = NS), and was zero in patients with nondiagnostic electrocardiograms.     

One-year outcomes of diabetic versus nondiabetic patients with non-Q-wave acute myocardial infarction treated with percutaneous transluminal coronary angioplasty

Risk factors and outcomes associated with non-Q-wave myocardial infarction (MI) in diabetics and nondiabetics were analyzed for 376 consecutive patients, 77 with diabetes (20%) and 299 nondiabetics (80%), who had non-Q-wave MI and had percutaneous transluminal coronary angioplasty (PTCA) performed before discharge from hospital during the period from January 1992 to February 1996. Diabetics were slightly older (64 +/- 10 years vs 61 +/- 12 years, p <0.053), had more prior coronary artery bypass grafting (CABG) surgery (27% vs 12%, p <0.001), and hypertension (77% vs 49%, p <0.001). There was no significant difference in unstable angina, saphenous vein graft PTCA, single versus multiple vessel disease, or history of MI. PTCA success rates for diabetics versus nondiabetics were similar (96% vs 97%, p = NS). In-hospital complications such CABG, recurrent MI, repeat PTCA, stroke, and death were not statistically significant between the 2 groups. At 1-year follow-up, survival in diabetics (92%) was similar to nondiabetics (94%, p = NS), although event-free survival (PTCA, CABG, MI, death) was worse in diabetics (55% vs 67% for nondiabetics, p <0.05). Although diabetic patients with non-Q-wave MI represent a cohort with more risk factors for poor outcome, aggressive in-hospital revascularization with PTCA results in an excellent short-term outcome as well as 1-year survival similar to the nondiabetic patients. However, total events at 1-year follow-up are more common in the diabetic patients, suggesting that more aggressive screening and therapy in follow-up may be warranted, and that a diabetic with non-Q-wave MI will require increased utilization of cardiovascular resources in the first year after the event.     

Impact of severity of coronary artery stenosis and the collateral circulation on the functional outcome of dyssynergic myocardium after revascularization in patients with healed myocardial infarction and chronic left ventricular dysfunction

The inferoposterior region of the triangle of Koch is hypothesized to be the location of the atrial insertion of the slow atrioventricular (AV) nodal pathway. However, the actual site of conduction slowing in the slow AV nodal pathway is unknown. Entrainment mapping during AV nodal reentry can localize the reentrant pathway as follows: the AH interval measured from the mapping catheter = A'H (where A' is the exit site of the reentrant circuit) minus A'A (the conduction time from A' to the site of mapping); the SH interval during entrainment = SA' (the conduction time from stimulus into the reentry circuit) plus A'H. Thus, in all cases, the SH interval should be greater than or equal to the AH interval, and the deltaAH-SH should increase as distance and conduction time (SA' and A'A) from the reentry circuit increases. Fourteen patients with typical AV nodal reentry (cycle length 346 +/- 62 ms) and 1 with fast-slow (cycle length 430 ms) underwent activation and entrainment mapping from 8 to 12 sites in the triangle of Koch and coronary sinus. Pacing was performed at 2 to 3 mA above threshold, at a cycle length 10 ms shorter than tachycardia. A mapping site was defined as being in close proximity to the circuit if the deltaAH-SH was within 120% of the shortest 20th percentile deltaAH-SH value from all measured sites. In the 14 typical cases, 45 of 83 sites (54%) in the anatomic slow pathway region fulfilled criteria for close proximity to the reentry circuit compared with 13 of 50 sites (26%) outside of this region (p = 0.005). For these patients, the shortest SH interval measured from any entrainment site was 294 +/- 58 ms (89 +/- 10% of tachycardia cycle length, range 70% to 119%), indicating that the site of slow conduction in the slow pathway during AV nodal reentrant tachycardia was distal to all mapped sites. Thus, during typical AV nodal reentry, the "slow" pathway does not conduct slowly, and its insertion is located at or within the inferoposterior or midseptal regions in most cases.     

Most frequent ways of the collateral circulation in occlusive coronary artery disease

By comparison of the sectional area of the fetal head of the fronto-occipital level in the height of the biparietalic diameter and the cross sectional area of thorax in the level area of the ventrical it was tried to determine the exspected birth weight. A mean deviation of 8,9% was found. Below a birth weight of 2500 g the presented calculation is only valid to some extend as in these cases the dominance proved in fetal development grounds of the head of the fetus becomes apparent.     

Myocardial contrast echocardiography versus dobutamine echocardiography for predicting functional recovery after acute myocardial infarction treated with primary coronary angioplasty

OBJECTIVES: We sought to compare myocardial contrast echocardiography with low dose dobutamine echocardiography for predicting 1-month recovery of ventricular function in acute myocardial infarction treated with primary coronary angioplasty. BACKGROUND: The relation between myocardial perfusion and contractile reserve in patients with acute myocardial infarction, in whom anterograde flow is fully restored without significant residual stenosis, is still unclear. METHODS: Thirty patients with acute myocardial infarction treated successfully with primary coronary angioplasty underwent intracoronary contrast echocardiography before and after angioplasty and dobutamine echocardiography 3 days after the index infarction. One month later, two-dimensional echocardiography and coronary angiography were repeated in all patients and contrast echocardiography in 18 patients. RESULTS: After coronary recanalization, 26 patients showed myocardial reperfusion within the risk area, although 4 did not. At 1-month follow-up, all patients had a patient infarct-related artery without significant restenosis. Both left ventricular ejection fraction and wall motion score index within the risk area significantly improved in the patients with reperfusion ([mean +/- SD] 38 +/- 8% vs. 48 +/- 12%, p < 0.005; and 2.35 +/- 0.5 vs. 2 +/- 0.6, p < 0.001, respectively), but not in those with no reflow. Of the 72 nonperfused segments before angioplasty, 27 showed functional improvement at follow-up. Myocardial contrast echocardiography had a sensitivity and a negative predictive value similar to dobutamine echocardiography in predicting late functional recovery (96% vs. 89% and 89% vs. 93%, respectively), but a lower specificity (18% vs. 91%, p < 0.001), positive predictive value (41% vs. 86%, p < 0.001) and overall accuracy (47% vs. 90%, p < 0.001). CONCLUSIONS: Microvascular integrity is a prerequisite for myocardial viability after acute myocardial infarction. However, contrast enhancement shortly after recanalization does not necessarily imply a late functional improvement. Thus, contractile reserve elicited by low dose dobutamine is a more accurate predictor of regional functional recovery after reperfused acute myocardial infarction than microvascular integrity.     

Risk factor reduction behaviours in coronary angioplasty and myocardial infarction patients

A recent study asked percutaneous transluminal coronary angioplasty (PTCA) patients in Saskatchewan (n = 210) to identify specific information surrounding their rehabilitation behaviours and motivation to change lifestyle. The scale used to elicit this information was developed and previously used to determine patient risk factor knowledge and lifestyle change behaviours among myocardial infarction (MI) patients during rehabilitation phases. The purpose of this article is to discuss the results of PTCA patients' responses and compare these findings to previously obtained data from MI patients. Risk factors most frequently reported by both PTCA and MI patients as causative factors of their heart problems included diet, job stress, low levels of exercise, and other patient-perceived factors. When asked about lifestyle restrictions post-hospitalization, PTCA patients reported more lifestyle restrictions in activities of daily living (recreation, job, social life, sexual activity and driving) following hospitalization than MI patients. Both groups of patients reported high levels of dietary changes made post-hospitalization but findings reflected that MI patients had initiated more modifiable risk factor changes overall than PTCA patients. Comparative results showed that MI patients were more likely to initiate risk factor reduction behaviours for modifiable factors such as smoking, weight reduction, job/family stress, and exercise than PTCA patients. These findings offer insight into differences between PTCA and MI patients with respect to cardiac rehabilitation behaviours and may suggest the need for different teaching-learning approaches and/or more focused patient education for PTCA patients. A goal of cardiac rehabilitation is to encourage patient initiation and maintenance of lifestyle modification behaviours based on identified risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Coronary artery perforation and delayed cardiac tamponade following balloon coronary angioplasty

A 62-year-old woman who had coronary artery disease and hypertrophic cardiomyopathy received percutaneous transluminal coronary angioplasty and endomyocardial biopsy. She withstood the procedure well. However, delayed pericardial tamponade occurred 2 hours after discharge from the cardiac catheterization laboratory. Despite pericardial drainage with a pigtail catheter and blood transfusion, the patient required emergency surgery. An oozing diagonal branch of the left anterior descending coronary artery was found. Ligation of this small branch stabilized the hemodynamics. Avoidance of improper positioning of the guide wire in the small coronary artery branch is important in preventing arterial wall trauma and subsequent perforation.