Percutaneous coronary angioscopy

In the last few years, major advances in catheter technology and miniaturization of fiber optics have allowed percutaneous coronary angioscopy to become a reality. Current angioscopy systems provide an outstanding image quality yielding precise evaluation of coronary atherosclerosis morphology in its various clinical manifestations. However, coronary angioscopy is a new diagnostic tool whose indications and specific role are yet to be delineated. Investigation on the potential roles of this technology are mainly centered in the field of acute coronary syndromes and interventional coronary therapies. In the near future, coronary angioscopy may play an important role in the investigation of the natural history of coronary artery disease, in the field of thrombolysis, and in the selection of specific therapy. In this article, coronary angioscopy system and technique are described and its potential clinical applications discussed.     

Sudden coronary death. Frequency of active coronary lesions, inactive coronary lesions, and myocardial infarction

BACKGROUND: The reported frequency of active coronary lesions (plaque rupture and coronary thrombosis) in sudden death due to coronary artery atherosclerosis (sudden coronary death) has varied from < 20% to > 80% of cases in previous series. In hearts lacking an active coronary lesion, sudden death has usually been attributed to a healed myocardial infarction. The purpose of the present study was to determine the frequency of active and inactive coronary lesions and myocardial infarction in individuals with sudden coronary death. METHODS AND RESULTS: The hearts of persons who died as a result of sudden coronary death underwent perfusion-fixation and postmortem angiography. An active coronary lesion was defined as a disrupted plaque, luminal fibrin/platelet thrombus, or both. We defined an inactive lesion as having a cross-sectional luminal stenosis of > or = 75% with neither plaque disruption nor luminal thrombus. Ninety hearts were examined (from 72 men and 18 women; mean age at the time of death, 51 +/- 10 years). Acute myocardial infarction was present in 19 (21% [acute myocardial infarction only in 9, both acute and healed myocardial infarction in 10]), healed myocardial infarction only in 37 (41%), and no myocardial infarction in 34 (38%). Active coronary lesions were identified in 51 (57%): acute thrombi plus disrupted plaques in 27, acute thrombi only in 21, and disrupted plaques only in 3. In hearts with acute myocardial infarction, active coronary lesions were significantly more prevalent than in hearts with only healed myocardial infarction or hearts lacking an acute or a healed myocardial infarction (89%, 46%, and 50%, respectively; P < .005). Hearts without acute or healed myocardial infarction and without active lesions were similar to hearts with active lesions with respect to heart weight and severity of epicardial coronary disease. CONCLUSIONS: Acute changes in coronary plaque morphology (thrombus, plaque disruption, or both) were found in 57% of cases of sudden coronary death. In hearts with myocardial scars and no acute infarction, active coronary lesions were identified in 46% of cases. Neither myocardial infarction (acute or healed) nor an active coronary lesion was present in 19% of hearts.     

Single coronary artery arising from the right coronary sinus. Report of two cases

The authors report two cases of single coronary artery arising from the right coronary sinus. Both patients had angina with reversible myocardial ischaemia on exercise Thallium scintigraphy. Coronary angiography showed single coronary artery arising from the right coronary sinus in both cases with severe stenosis of the right coronary artery in the first and occlusion of the right coronary artery in the second patient. Both underwent surgical revascularisation with a good result. Single coronary artery is a rare congenital abnormality (approximately 0.36 per 1,000) diagnosed at autopsy until 1963, and thereafter at coronary angiography. A review of the literature shows that an equal number of single coronary arteries arise from the right as from the left coronary sinus: there does not seem to be an increased risk of complication when a branch runs between the aorta and pulmonary artery. On the other hand, single coronary arteries arising from the right coronary sinus seem to be more commonly associated with atherosclerosis than a network with two coronary arteries, but when the lesions are proximal, the risk is high. Revascularisation is indicated only when myocardial ischaemia has been documented.     

Soluble P-selectin is released into the coronary circulation after coronary spasm

BACKGROUND: The glycoprotein P-selectin is an adhesion molecule involved in the property change of leukocytes at the initiation of the inflammatory process. The purpose of the present study was to determine whether acute myocardial ischemia induced by coronary spasm causes an acute inflammatory response in the coronary circulation. METHODS AND RESULTS: We examined plasma soluble P-selectin levels in the coronary sinus and the aortic root simultaneously in 16 patients with coronary spastic angina before and after left coronary artery spasm induced by intracoronary injection of acetylcholine and in 15 patients with stable exertional angina before and after acute myocardial ischemia induced by rapid atrial pacing. Ten control patients with chest pain but normal coronary arteries and no coronary spasm also received intracoronary acetylcholine. Plasma soluble P-selectin levels were increased significantly in the coronary sinus (32.8 +/- 3.6 to 52.8 +/- 5.9 ng/mL, P < .001) and in the aortic root (34.6 +/- 3.7 to 41.9 +/- 4.4 ng/mL, P < .05) after the attacks in the coronary spastic angina group but remained unchanged in the stable exertional angina group after the attacks and in the control group after the administration of acetylcholine. Furthermore, the coronary sinus-arterial difference of soluble P-selectin increased significantly after the attacks in the coronary spastic angina group (-1.8 +/- 2.2 to 10.9 +/- 2.7 ng/mL, P < .001). CONCLUSIONS: Our data indicate that soluble P-selectin is released into the coronary circulation after coronary artery spasm. We conclude that coronary artery spasm may induce the leukocyte adhesion in the coronary circulation and may lead to myocardial damage.     

Aortic dissection extending from the left coronary artery during percutaneous coronary angioplasty

A 72-year-old woman with acute aortic dissection as a complication of percutaneous coronary angioplasty was successfully treated. She received a graft replacement of the ascending aorta as well as triple coronary artery bypass grafts. The dissection had extended from the left coronary artery. Although acute aortic dissection is a rare complication of percutaneous coronary angioplasty, physicians and cardiac surgeons should keep its potential occurrence in mind.     

Left coronary artery-left ventricle fistula with right coronary artery spasm

A 72-year-old woman was admitted to our hospital for evaluation of chest pain. Coronary angiography showed a left coronary artery-left ventricle fistula. An acetylcholine provocation test induced vasoconstriction of the right but not the left coronary artery. Her chest pain was not relieved by combined therapy with isosorbide dinitrate, diltiazem and nicorandil. Because of the coronary spasm, beta-blockers could not be used. However, her chest pain was relieved after the administration of a minor tranquilizer. Thus, the patient's chest pain was unlikely to be associated with either the fistula or the coronary spasm.     

Left coronary artery transit time in latent coronary heart disease

In a group of 104 cases with possible silent coronary heart disease, 36 had normal angiographic findings and 68 significant coronary artery disease. The transit time of the contrast medium in the left coronary artery was significantly shorter in cases with abnormalities of the artery than in non-afflicted cases. The extent of arterial disease seemed to influence the transit time inversely, whereas the location of the abnormalities did not influence the transit time.     

Clamp for coronary artery operations

Aortocoronary bypass grafting is an accepted procedure for ischemic heart disease. Proper visualization of the coronary artery is mandatory for good surgical anastomosis. This is essential when a coronary operation is performed without cardioplegia or in surgical procedures without bypass support. For better visualization of a coronary artery, we are presenting a coronary artery clamp. We have used this clamp in minimally invasive coronary artery operations to achieve a bloodless field.     

Unroofed coronary sinus syndrome

Unroofed coronary sinus syndrome or coronary sinus septal defect is a rare congenital cardiac anomaly. We performed corrective operations in 9 patients with such condition. Of them, seven patients had the completely unroofed coronary sinus and persistent left superior vena cava (PLSVC) directly draining into the left atrium (LA). One patient had PLSVC and the partially unroofed terminal portion of the coronary sinus (CS), or sinus ostium open into LA. Another patient had total anomalous pulmonary vein connection and the partially unroofed mid-portion of CS without PLSVC. The operative methods of the unroofed coronary sinus included: ligating PLSVC and repairing ostium primum or secundum atrial septal defects in 4 cases; creating an intra-atrial tunnel from PLSVC to the right atrium (RA) and repairing the atrial septal defect in 2 cases; reconstructing the intra-atrial septal with a patch as a baffle to guide PLSVC or sinus ostium respectively towards RA in 2 cases; enlarging the defect on the coronary sinus roof and repairing the atrial septal defect of the coronary sinus type in one case. No patient died in this group. Because unroofed coronary sinus syndrome has atypical clinical manifestation and usually complicates varied congenital anomalies, its preoperative diagnosis is very difficult in some times and may draw the reliable support from echocardiography and catheterization. The operative program and method must depend not only upon its type but also upon PLSVC presence of absence, and communication between PLSVC and RSVC.     

The pathophysiologic basis of acute coronary insufficiency. Observations favoring the hypothesis of intermittent reversible coronary obstruction

Clinical, coronary angiographic, and myocardial metabolic data were analyzed to test alternative hypotheses for the pathophysiologic basis of acute coronary insufficiency. The initial incidence of coronary collaterals was not low in relation to coexisting coronary obstructive disease; the early subsequent coronary occlusion rate was high; and in asymptomatic intervals during the acute illness, myocardial hypoxia was infrequent and coronary reserve substantial. These observations support the hypothesis that the acute coronary insufficiency syndrome is caused by reversible coronary ischemic episodes rather than by a new permanent atherosclerotic lesion.     

Three-dimensional respiratory-gated MR angiography of coronary arteries: comparison with conventional coronary angiography

OBJECTIVE: MR coronary angiography is most often performed using two-dimensional techniques. Although three-dimensional (3D) acquisitions do have important advantages, they take too long for a single breath-hold and are thus susceptible to respiratory motion artifacts. The purpose of this study was to investigate the accuracy of a unique respiratory-gated 3D MR angiographic technique in identifying the proximal coronary arteries in patients suspected of having coronary artery disease. In addition, we investigated the capability of this technique to detect proximal stenoses. SUBJECTS AND METHODS: We performed a prospective blinded study in 20 patients who were referred for conventional coronary angiography. A cardiac-gated 3D gradient-echo sequence with fat suppression was used. Retrospective respiratory gating was performed using navigator echoes of the diaphragm position. Using multiplanar reformatting, two independent readers blindly analyzed the data sets for visualization of major coronary arteries, lengths of imaged segments, and detection of significant stenoses (> 50% occlusion of the luminal diameter by conventional angiography). RESULTS: Seventy-seven of 80 (96%) coronary arteries were positively identified. In one patient, an anomalous coronary anatomy was readily identified and confirmed by conventional angiography. The average lengths of the imaged segments of the right, left main, left anterior descending, and left circumflex coronary arteries were 58 +/- 13 mm, 9 +/- 5 mm, 59 +/- 16 mm, and 24 +/- 10 mm, respectively. Overall sensitivity for the detection of stenoses was low (38%), with a specificity of 95%. Interobserver agreement was 0.92, with a kappa value of 0.65. CONCLUSION: Respiratory-gated 3D MR angiography allows accurate identification of proximal coronary arteries and may be valuable for 3D imaging of coronary anomalies. Further technical improvements are required to enhance the value of the technique in detecting stenoses.     

Right coronary artery cirsoid with fistulous connection to the coronary sinus

A 61-yr-old woman was referred to our hospital for evaluation of a suspected right atrial myxoma. The transesophageal echocardiogram suggested the presence of an anomalous right coronary artery with fistulous connection to the coronary sinus. At cardiac catheterization, an oxygen step-up in the right atrium indicated a 1.3:1.0 left-to-right shunt. Aortic root angiography showed a large and calcified right coronary artery cirsoid draining to the coronary sinus, which appeared remarkably dilated. In this rare anomaly, cardiac catheterization is necessary, not only to quantify the magnitude of the left-to-right shunt, which is an important requirement for the indication to surgical treatment, but also to confirm the echocardiographic diagnosis.     

The role of coronary angiography and coronary revascularization before noncardiac vascular surgery

OBJECTIVE: To determine whether preoperative coronary angiography and revascularization improve short-term outcomes in patients undergoing noncardiac vascular surgery. DESIGN: Decision analysis. PATIENTS: Patients undergoing elective vascular surgery who had either no angina or mild angina and a positive dipyridamole-thallium scan result. INTERVENTIONS: Three strategies were compared. The first strategy was to proceed directly to vascular surgery. The second was to perform coronary angiography, followed by selective coronary revascularization, before proceeding to vascular surgery and to cancel vascular surgery in patients with severe inoperable coronary artery disease (CAD). The third was to perform coronary angiography, followed by selective coronary revascularization, before proceeding to vascular surgery and to perform vascular surgery in patients with inoperable CAD. MAIN OUTCOME MEASURES: Mortality, nonfatal myocardial infarction, stroke, uncorrected vascular disease, and cost. All outcomes were assessed within 3 months. RESULTS: Proceeding directly to vascular surgery led to lower morbidity and cost in the base case analysis. The coronary angiography strategy led to higher mortality if vascular surgery would proceed in patients with inoperable CAD, but led to slightly lower mortality if vascular surgery were canceled in patients with inoperable CAD. The coronary angiography strategy also led to lower mortality when vascular surgery was particularly risky. CONCLUSIONS: Decision analysis indicates vascular surgery without preoperative coronary angiography generally leads to better outcomes. Preoperative coronary angiography should be reserved for patients whose estimated mortality from vascular surgery is substantially higher than average.     

Changes in coronary vasodilation in hypertensive patients with angiographically normal coronary arteries

In normal subjects, coronary arteries dilate in response to sympathetic stimulation evoked by the cold pressor test. Similarly, in normal coronary arteries the increase in blood flow velocity induced by papaverine results in flow-dependent coronary dilation. In order to assess the coronary responses to both stimuli in hypertensive patients, variations of proximal left anterior descending coronary artery diameters and coronary blood flow velocity have been measured using quantitative coronary angiography and intracoronary Doppler in 10 control subjects and in 12 hypertensive patients. All the patients had angiographically normal coronary arteries. Total serum cholesterol, triglycerides, HDL- and LDL-cholesterol were within normal range in all patients. All patients were nonsmokers and none of them had diabetes mellitus. During the cold pressor test (hands immersed in ice water for 120 s), the rate-pressure product and coronary blood flow velocity increased respectively by 33 +/- 9% (p < 0.001) and 51 +/- 26% (p < 0.05) in control subjects, by 28 +/- 18% (p < 0.001) and 68 +/- 52% (p < 0.05) in hypertensive patients. In control subjects, coronary arteries dilated by + 12.0 +/- 4.4% (p < 0.001), and constricted by -10.3 +/- 8.5% (p < 0.001) in hypertensive patients. After injection of 10 mg of papaverine into the distal left anterior descending coronary artery, proximal left anterior descending coronary artery dilated by + 17.0 +/- 10.6% (p < 0.001) in control subjects, and did not vary (-0.7% +/- 10.6%) in hypertensive patients, when blood flow velocity was increased respectively by 449 +/- 97% and 383 +/- 103% (p < 0.001 in both groups).(ABSTRACT TRUNCATED AT 250 WORDS)     

Assessing the coronary circulation in hypertension

Systemic arterial hypertension is one of the major risk factors for coronary artery disease, coronary microangiopathy, and left ventricular hypertrophy, all of which can potentially lead to cardiac failure and sudden cardiac death. Coronary flow reserve is defined as the maximal increase in coronary flow above its resting, autoregulated level for a given perfusion pressure. In arterial hypertension functional and structural alterations are observed at the level of epicardial vessels as well as in resistive vessels requiring sophisticated approaches to assess coronary flow reserve and thus myocardial perfusion. Electrocardiographic tests and echocardiography can be regarded as monitoring and screening methods. Myocardial scintography is useful to semiquantitatively estimate hypertension-associated perfusion abnormalities, whereas positron emission tomography provides the only quantitative approach of a non-invasive technique for myocardial blood flow measurement. Invasive methods for the assessment of coronary blood flow need cardiac catheterization procedures, such as techniques requiring catheterization of the coronary sinus, angiographic methods, and guidewire based methods. Thermodilution and venous oxymetry in the coronary sinus systematically underestimate coronary flow reserve and are thus considered as only semiquantitative approaches. In contrast, the gas chromatographic argon method allows a quantitative measurement of coronary blood flow at baseline and during maximum vasodilation; thus it is possible to distinguish between an altered autoregulated and maximal flow as the major cause of a reduced coronary flow reserve and to evaluate long-term therapeutic interventions in hypertensive hearts. Videodensitometric and angiographic methods should be restricted only to patients with coronary microangiopathy or with coronary single-vessel disease. Guidewire-based Doppler techniques are suitable to semiquantitatively assess coronary flow reserve with a considerable spatial and time resolution. Myocardial biopsies may gain insight into hypertension-associated structural alterations in small arterioles. Long-term treatment of hypertensive heart disease aims to normalize blood pressure, to reduce left ventricular hypertrophy and to achieve cardioreparation including reversal of the abnormal structure and function of coronary circulation. Based on the different methods for assessment of coronary circulation the therapeutic value of different classes of antihypertensive therapeutics will be evaluated in this overview.     

Radiofrequency thermal balloon coronary angioplasty: a new device for successful percutaneous transluminal coronary angioplasty

OBJECTIVES: The purpose of this study was to evaluate the effects of thermal balloon percutaneous transluminal coronary angioplasty using radiofrequency energy in the treatment of patients with failed coronary angioplasty and complex lesions. In addition, we evaluated restenosis after radiofrequency thermal balloon applications. BACKGROUND: The efficacy of coronary angioplasty is limited by the relatively low success rate in complex lesions and the high frequency of restenosis. Few reports have studied the combined effects of pressure and laser thermal energy. This study describes a new device for coronary angioplasty using radiofrequency thermal energy. METHODS: Thirty-two patients with failed conventional coronary angioplasty or complex lesions were treated with radiofrequency thermal balloon coronary angioplasty. Radiofrequency energy was delivered up to 11 times in exposures ranging from 30 to 60 s in duration. This combined effect allowed the vascular wall to be heated to temperatures ranging from 60 to 70 degrees C. Follow-up coronary angiography was performed, on average, 6 months after the procedure. RESULTS: Successful radiofrequency coronary angioplasty was achieved in 28 (82%) of 34 lesions. There was one abrupt coronary artery occlusion (3%) and no death, perforation or dissection. Angiographic restenosis occurred in 14 (56%) of 25 lesions. CONCLUSIONS: In patients with failed coronary angioplasty and difficult complex lesions, radiofrequency coronary angioplasty could potentially improve angioplasty success rates and may have important implications for bailout cases with abrupt occlusion. However, restenosis remains a significant problem.     

Anatomic variations of the coronary arteries

PURPOSE: To study the coronary arteries and their main branches showing the aspects of source, trajectory and anastomoses of these vessels at the subepicardial level. METHODS: The study was carried out on 110 adult human hearts, of both sexes, fixed in 10% formaldehyde solution. The pericardium was removed to expose the coronary arteries and their branches at the subepicardial level. RESULTS: In 38.18% of the cases the left coronary artery presented a trifurcation into anterior interventricular, circunflex and left marginal branches (35.70%) and into anterior interventricular, circunflex and lateral branches (64.30%). In 60% of the hearts examined, the left coronary artery presented a bifurcation into anterior interventricular and circunflex branches. In 1.82% of the cases these two branches arise directly from the aorta. An anastomosis, at the subepicardial level, between the anterior and posterior interventricular branches was observed in 56.36% of the hearts. In 88.18% the posterior interventricular branch arised from the right coronary artery, whereas in 11.82% this vessel arises from the circunflex branch. Anastomoses between the right coronary artery and the circunflex branch were found in 10% of the hearts (crux cordis). The dominance of the right coronary artery was present in 69.09% of the cases, of the left coronary artery in 11.82% and in 19.09% of the hearts had balanced distribution. CONCLUSION: The coronary arteries and their main branches present a great quantity of variations with regard to source, trajectory and anastomoses. This knowledge is important for the interpretation of coronary angiography and surgical myocardial revascularization.     

Methods for coronary functional assessment

Functional evaluation of coronary vasomotion encompasses the assessment of dynamic changes in coronary lumen, vessel wall, blood flow, intracoronary pressure and myocardial perfusion in response to specific pharmacologic stimuli. These parameters are obtained to characterize mechanisms of physiologic regulation and to evaluate pathophysiologic processes and potential therapeutic strategies, especially with regard to the development of coronary atherosclerosis. To this end, a variety of direct (invasive) and indirect (non-invasive) diagnostic tools are employed. Among the invasive methods are registration of intracoronary Doppler flow, coronary pressure measurements, quantitative coronary angiography and intravascular ultrasound. The non-invasive modalities consist of coronary Doppler echocardiography, positron emission tomography, myocardial scintigraphy and magnetic resonance imaging. Because of the different technical and physiological principles involved, these methods are complementary by providing independent access to different aspects. The combined invasive functional testing as employed in the cardiac catheterization laboratory allows for a simultaneous synopsis of high-resolution coronary imaging and direct measurement of physiologic parameters during local application of defined pharmacologically active substances. However, the demands in terms of equipment, time and operator skills are high and limit this combined invasive approach to specialized centers. Besides these research purposes, a number of functional methods has entered the clinical arena. They are employed to evaluate the hemodynamic significance of coronary lesions and to assess functional outcome of therapeutic interventions in the catheterization laboratory. The underlying principles and applications of the different methods are described and an overview of selected results is presented.     

The optimal mode of coronary revascularization for diabetics. A risk-adjusted long-term study comparing coronary angioplasty and coronary bypass surgery

AIMS: Some recent studies have reported-superior outcomes for diabetic patients following coronary bypass surgery compared with coronary angioplasty. However, the available data are conflicting, are based on relatively small numbers of diabetic patients, and have limited duration of follow-up. The aims of this study were to compare risk adjusted long-term survival in diabetic patients following first-time revascularization via either coronary bypass surgery or coronary angioplasty; and, to identify variables independently associated with mortality. METHODS AND RESULTS: This was a two centre database project involving 15809 patients undergoing either coronary angioplasty or coronary bypass surgery as their initial revascularization procedure. Diabetes was present in 1938 (12%). Mean follow-up was 4.6+/-2.7 years for angioplasty and 6.6+/-4.3 years surgery diabetic patients. Multivariable time-related analyses in the hazard function domain for death were performed. Overall ten-year survival for pharmacologically treated diabetics was better after coronary bypass surgery (60%) than angioplasty (46%, <0.0001). However, the risk-adjusted survival advantage conferred by bypass surgery over angioplasty was strongest for patients receiving oral agents for diabetic control (75% vs 62%) and less impressive for diet (84% vs 81%) and insulin-treated diabetics (63% vs 64%). The major factors independently associated with worse outcome after angioplasty were incomplete revascularization, and the use of a sulfonylurea agent. The use of the left internal mammary graft improved survival in surgical patients. CONCLUSIONS: In general, diabetic patients had better long-term survival after bypass surgery than angioplasty. Incomplete revascularization and sulfonylurea therapy worsened outcome after angioplasty, and use of the left internal mammary improved outcome after bypass surgery.     

Anomalous origin of the right coronary artery from the left anterior descending coronary artery

A 77-year-old male presented with a recent posterior myocardial infarction for coronary angiography. This angiogram revealed a rare, previously unreported anomalous origin of the right coronary artery from the proximal left anterior descending coronary artery distal to the first major diagonal branch.