George K. David

Clinical, Angiographic and Hemodynamic Predictors of Recruitable Collateral Flow Assessed During Balloon Angioplasty Coronary Occlusion

OBJECTIVES We sought to determine the predictive value of factors influencing coronary collateral vascular responses in humans. BACKGROUND There is limited information on the factors responsible for coronary collateral vascular development, despite the protective effect of collateral vessels in ischemic syndromes. METHODS Angiography of the contralateral artery was performed during balloon coronary occlusion in 105 patients with single-vessel disease (left anterior descending coronary artery in 69 patients, left circumflex coronary artery in 4 patients, right coronary artery in 32 patients) and normal left ventricular function. Collateral vessels were graded according to the classification of Rentrop. The relative collateral vascular resistance was calculated in a subgroup of 34 patients by means of aortic pressure, coronary wedge pressure and collateral flow, defined as the transient increase of coronary blood flow velocity of the contralateral artery during balloon coronary occlusion. Ischemia during coronary occlusion was evaluated by the ST segment shift (mV) in a 12-lead electrocardiogram (ECG). RESULTS A multivariate logistic analysis of clinical and angiographic variables revealed duration of angina (> or = 3 months, p < 0.0001), lesion severity (> or = 75% diameter stenosis, p < 0.0001) and proximal lesion location (p = 0.02) as independent factors positively associated with recruitability of collateral vessels, whereas the use of nitrates exerted an independent negative effect (p = 0.01). The regression equation yielded an overall predictive accuracy of 80%. The presence of recruitable collateral vessels during coronary occlusion resulted in a higher coronary wedge/aortic pressure ratio (mean [+/- SD] 0.35 +/- 0.13 vs. 0.27 +/- 0.12, p < 0.005), a lower relative collateral vascular resistance (6.7 +/- 7.4 vs. 21.3 +/- 10, p < 0.001) and a reduction of ECG signs of ischemia (0.14 +/- 0.19 vs. 0.38 +/- 0.33 mV, p < 0.001). The relative collateral vascular resistance was the best predictor for recruitability of collateral vessels compared with the other variables related to collateral vascular growth (p < 0.05). CONCLUSIONS Clinical and angiographic variables predict recruitability of collateral vessels with an 80% overall accuracy. These findings are important for risk stratification of patients undergoing interventions for ischemic coronary syndromes.

Early identification of patients developing late in-hospital ventricular fibrillation after discharge from the coronary care unit

Abstract In an initial retrospective study, covering 3 years, 30 (3 percent) of 966 patients consecutively discharged from the coronary care unit, were found to have sustained late in-hospital ventricular fibrillation 10 to 38 days after myocardial infarction. Of these 30 patients, 18 (60 percent) died in the hospital and 14 (47 percent) had anteroseptal infarction complicated by right or left bundle branch block. In a later prospective study, covering 2 1 2 years, 47 consecutive coronary care unit survivors with anteroseptal infarction complicated by right or left bundle branch block were kept in the monitoring area for 6 weeks after infarction. Seventeen of these 47 (36 percent) sustained late in-hospital ventricular fibrillation. Neither the type nor the duration of bundle branch block affected the Incidence of late in-hospital ventricular fibrillation. Six (35 percent) of the 17 patients with ventricular fibrillation died in the hospital. Three died from ventricular fibrillation, and of six patients treated with infarctectomy, another three died postoperatively. Of 11 hospital survivors with late in-hospital ventricular fibrillation, followed up for 1 to 30 months, 1 died suddenly within 1 month. Of the remaining 884 patients who were not kept in the monitoring area after coronary care unit discharge, 8 (0.9 percent) sustained late ventricular fibrillation (with 3 in-hospital deaths) and 4 (0.5 percent) others died suddenly in hospital. The results indicate that coronary care unit survivors with anteroseptal infarction complicated by right or left bundle branch block should be kept in the monitoring area for 6 weeks.

Severity of single-vessel coronary arterial stenosis and duration of angina as determinants of recruitable collateral vessels during balloon angioplasty occlusion

To determine the factors that influence the presence of collateral vessels during coronary occlusion, we performed standardized contrast injection of the contralateral coronary artery in 58 consecutive patients, without previous myocardial infarction, undergoing percutaneous transluminal coronary angioplasty for 1-vessel disease (left anterior descending artery in 45, right coronary artery: in 10 and left circumflex artery in 3). The presence of collateral vessels during coronary occlusion, defined as partial or complete epicardial opacification by collateral vessels of the vessel dilated, was related to clinical, angiographic and electrocardiographic parameters. The angiographic appearance of collateral vessels during balloon inflation showed a weak, although statistically significant, correlation to the percent diameter stenosis before angioplasty (r = 0.28; p = 0.03) and the duration of angina (r = 0.37; p = 0.004). By combining lesion severity with the duration of angina, collateral vessels during coronary occlusion were particularly related to a lesion severity greater than or equal to 70% and duration of angina greater than or equal to 3 months (p less than 0.001). Furthermore, the presence of collateral vessels was associated with an absence of ST-segment shift (greater than or equal to 1 mm) during 1 minute of coronary occlusion (p less than 0.001).

Randomised trial of excimer laser angioplasty versus balloon angioplasty for treatment of obstructive coronary artery disease

BACKGROUND Excimer laser coronary angioplasty is reported to give excellent procedural results for treatment of complex coronary lesions, but this method has not been compared with balloon angioplasty in a randomised trial. METHODS Patients (n = 308) with stable angina and coronary lesions longer than 10 mm on visual assessment were included. 151 patients (158 lesions) were assigned randomly to laser angioplasty and 157 (167 lesions) to balloon angioplasty. The primary clinical endpoints were death, myocardial infarction, coronary bypass surgery, or repeat coronary angioplasty of the randomised segment during 6 months of follow-up. The primary angiographic endpoint was the minimal lumen diameter at follow-up in relation to the baseline value (net gain), as determined by quantitative coronary angiography. FINDINGS Laser angioplasty was followed by balloon angioplasty in 98% of procedures. The angiographic success rate was 80% in patients treated with laser angioplasty compared with 79% in patients treated with balloon angioplasty. There were no deaths. Myocardial infarction, coronary bypass surgery, and repeat angioplasty occurred in 4.6%, 10.6%, and 21.2%, respectively, of the patients in the laser angioplasty group compared with 5.7%, 10.8%, and 18.5% of the balloon angioplasty group. Net mean (SD) gain in minimal lumen diameter was 0.40 (0.69) mm in patients treated with laser angioplasty and 0.48 (0.66) mm in those treated with balloon angioplasty (p = 0.34). The restenosis rate (> 50% diameter stenosis) was 51.6% in the laser angioplasty group versus 41.3% in the balloon angioplasty group (p = 0.13). INTERPRETATION Excimer laser angioplasty followed by balloon angioplasty provides no benefit additional to balloon angioplasty alone with respect to the initial and long-term clinical and angiographic outcome in the treatment of obstructive coronary artery disease.

Two-dimensional echocardiography during percutaneous transluminal coronary angioplasty

In order to study myocardial and clinical events during transient coronary occlusion in humans, two-dimensional echocardiography was continuously performed in 15 patients undergoing 49 balloon inflations during percutaneous transluminal coronary angioplasty (PTCA). Transient segmental asynergy developed in all patients 8 +/- 3 seconds after balloon inflation and returned to baseline 19 +/- 8 seconds after balloon deflation. Segmental dyskinesis was seen in only 8 of 11 patients undergoing PTCA of the left anterior descending artery (LAD). A wall motion score, based on degree of asynergy of 13 segments of the left ventricle, was significantly higher during LAD than during right coronary artery inflation (7.9 +/- 1.3 vs 4.0 +/- 1.4, p less than 0.01). Left ventricular size index increased significantly during balloon inflation, from 179 +/- 9 to 196 +/- 10 mm (p less than 0.01). Four patients developed transient ST segment changes in the extremity leads of the ECG and five patients had angina pectoris. The very first sign of ischemia in three patients, who developed all of these symptoms together, was consistently asynergy, followed by ECG changes, and last, angina pectoris. Thus during PTCA, transient asynergy and left ventricular dilatation develop, which are often clinically silent.

Echocardiographic-cineangiographic correlation in detecting left ventricular aneurysm: A prospective study of 422 patients

Four hundred twenty-two consecutive patients with a documented myocardial infarction underwent cardiac catheterization and echocardiographic examination. Adequate two dimensional echocardiograms were obtained in 386 patients (91 percent). Left ventricular aneurysm was defined echocardiographically and cineangiographically as a well demarcated bulge in the contour of the left ventricular wall during both diastole and systole, demonstrating dyskinesia or akinesia. Cineangiography was considered as the standard for the diagnosis of left ventricular aneurysm. The site of aneurysm was mainly anteroapical. An aneurysm was judged present on cineangiography in 111 patients and on echocardiography in 118 patients. The presence and absence of an aneurysm echocardiographically correlated in 103 and 260 patients, respectively, with cineangiography. In 8 patients a cineangiographically identified aneurysm was not manifested echocardiographically, whereas in 15 patients an aneurysm identified on echocardiography was not evident on cineangiography. Thus two dimensional echocardiography can detect or exclude a left ventricular aneurysm with a high level of sensitivity (93 percent) and specificity (94 percent).

Safety of low dose heparin in elective coronary angioplasty.

OBJECTIVES: To evaluate the safety of a low dose of heparin in consecutive stable patients undergoing elective percutaneous transluminal coronary angioplasty (PTCA). DESIGN: Open prospective study in a single centre. PATIENTS: 1375 consecutive patients had elective PTCA (1952 lesions: type A 11%, B1 34%, B2 36%, and C 19%). There were no angiographic exclusion criteria. INTERVENTIONS: A bolus of 5000 IU heparin was used as the standard anticoagulation regimen during PTCA. The sheaths were removed immediately after successful completion of the procedure. Prolongation of heparin treatment was left to the operators discretion. MAIN OUTCOME MEASURES: Procedural success was defined as < 50% residual stenosis without death from any cause, acute myocardial infarction, urgent coronary bypass surgery, or repeat angioplasty within 48 hours for acute recurrent ischaemia; the need for prolonged heparinisation; and the occurrence of puncture site complications. RESULTS: Procedural success without clinical events was achieved in 90% of patients. Mortality was 0.3%; coronary bypass surgery was performed in 1.7% of the procedures. The rate of myocardial infarction was 3.3%; repeat angioplasty within 48 hours was carried out in 0.7% of patients. A total of 89.1% of the patients were treated according to the protocol. Prolonged treatment with heparin was considered necessary in 123 patients (8.9%). Repeat angioplasty for abrupt closure was performed in two patients shortly after sheath removal and in two during prolonged heparinisation. Puncture site complications occurred in 2.1% of patients (low dose heparin 1.9% and prolonged heparinisation 4.9%). CONCLUSION: Elective PTCA can be safely performed using a low dose of heparin, with a negligible risk for subacute closure. Low dose heparin may reduce the incidence of puncture site complications, shorten hospitalisation, and enable out-patient angioplasty.

Pharmacological Modulation of the Human Collateral Vascular Resistance in Acute and Chronic Coronary Occlusion Assessed by Intracoronary Blood Flow Velocity Analysis in an Angioplasty Model

BACKGROUND The pharmacological responsiveness of the coronary collateral circulation in humans has been studied only by indirect means. METHODS AND RESULTS Patients with one-vessel disease and recruitable (n = 14) or spontaneously visible (n = 24) collateral vessels were studied during coronary angioplasty. Collateral flow in the recipient coronary artery was determined with a 0.014-in Doppler guide wire during balloon coronary occlusion and expressed as the diastolic blood flow velocity integral (dVi). Collateral blood flow velocity, mean aortic pressure (Pao), and coronary wedge pressure (Pw) were used to calculate the collateral vascular resistance index: Rcoll = (Pao-Pw)/ dVi (mm Hg/cm) and the peripheral vascular resistance index of the recipient coronary artery: R4 = Pw/dVi (mm Hg/cm). Adenosine (12 to 18 micrograms) and nitroglycerin (0.2 mg) were injected as a bolus in the donor coronary artery during subsequent balloon inflations to assess their effect on these hemodynamic variables. The administration of adenosine or nitroglycerin in patients with recruitable collateral vessels did not induce a change in dVi and Pw/Pao ratio. In patients with spontaneously visible collateral vessels, dVi increased from 8.0 +/- 4.5 to 10.8 +/- 8.0 cm (P = .01) after adenosine and from 7.4 +/- 4.5 to 10.3 +/- 6.9 cm (P = .003) after nitroglycerin. The Pw/Pao ratio remained unchanged after adenosine and nitroglycerin. Rcoll decreased from 10.3 +/- 9.5 to 8.6 +/- 8.5 mm Hg/cm (P = .01) after adenosine and from 11.6 +/- 10.4 to 8.3 +/- 8.9 mm Hg/cm (P < .001) after nitroglycerin. R4 decreased from 7.7 +/- 5.5 to 5.9 +/- 5.1 mm Hg/cm (P < .001) after adenosine and from 8.4 +/- 6.6 to 7.1 +/- 7.2 mm Hg/cm (P = .01) after nitroglycerin. CONCLUSIONS Coronary collateral blood flow can be increased with adenosine and nitroglycerin in patients with one-vessel disease and spontaneously visible collateral vessels, which is in contrast to patients with recruitable collateral vessels. This effect is the result of a reduction in the collateral vascular resistance and peripheral vascular resistance of the recipient coronary artery.

Early ambulation after coronary angioplasty and stenting with six French guiding catheters and low-dose heparin

The safety and feasibility of early ambulation was evaluated prospectively in 907 patients undergoing elective coronary angioplasty and stenting with the use of 6Fr guiding catheters, low-dose heparin (5,000 IU), and immediate postprocedural sheath removal by comparing ambulation after 4 hours with immobilization for at least 12 hours. Because no excess in puncture site complications (2.3% vs 2.2%) could be demonstrated after 4-hour ambulation, it is concluded that early ambulation after 6Fr guiding catheter angioplasty by the femoral route with low-dose heparin is feasible, safe, and may facilitate a shorter hospital stay.

Spectral analysis of flow velocity in the contralateral artery during coronary angioplasty: a new method for assessing collateral flow.

OBJECTIVES The present study was designed to evaluate a new method for assessing coronary collateral flow and resistance in conscious humans. BACKGROUND Earlier pathomorphologic and invasive studies have indicated that collateral vessels are important for salvage of myocardium at risk in acute myocardial infarction. Only a few clinical studies have attempted to express the development of the collateral vascular bed in terms of flow or resistance. METHODS Angiography and flow velocity measurements of the contralateral coronary artery were performed in 38 patients undergoing coronary angioplasty for one-vessel disease. Coronary flow velocity was assessed by zero-crossing frequency analysis in 37 patients and, additionally, by fast Fourier transform spectral analysis in 23. Collateral flow was determined by the decrease of flow velocity after balloon deflation. Mean aortic pressure and coronary wedge pressure were assessed for calculation of collateral vascular resistance. RESULTS Angiography of the contralateral artery during balloon inflation revealed the presence of collateral vessels in 26 patients (recruitable collateral vessels in 19). Fast Fourier transform spectral analysis demonstrated a significant transient increase of flow velocity during brief coronary occlusion in 15 patients with collateral vessels compared with 8 patients without collateral vessels (4.8 +/- 1.3% vs. 23.4 +/- 17.2%, p < 0.001). A transient increase in flow velocity (> 10%) was less evident by zero-crossing frequency analysis than by fast Fourier transform spectral analysis (sensitivity 8% vs. 87%). The relative resistance of the collateral vascular bed was significantly reduced when collateral vessels were present during coronary occlusion (4.4 +/- 3.8 vs. 16.9 +/- 4.6, p < 0.001). Furthermore, electrocardiographic signs of ischemia were less present in those 15 patients with collateral vessels (p < 0.05). CONCLUSIONS The beneficial effect of collateral vessels during brief coronary occlusion is exerted by a significant increase of flow in the contralateral artery in combination with a reduced resistance in the collateral vascular bed. The method presented is capable of expressing the development of the collateral vascular bed in terms of flow and resistance.