ST segment response to acute coronary occlusion: coronary hemodynamic and angiographic determinants of direction of ST segment shift

To assess the relationship between the direction of ST segment response to transient coronary occlusion and collateral function, we studied 25 patients with diagnostic ST segment changes during transient occlusion of the proximal left anterior descending artery (LAD). Electrocardiographic leads I, II, V2, and V5; left ventricular filling, aortic, and distal coronary pressures; and great cardiac vein flow were measured during percutaneous transluminal coronary angioplasty (PTCA) of the LAD. During a 1 min LAD balloon occlusion, 16 patients had reversible ST elevation (group I) and nine patients had ST depression (group II). The ST responses in individual patients were consistent during repeated occlusions, and ST depression never preceded ST elevation. Angiography before PTCA showed less severe LAD stenosis in group I (69 +/- 15%) than in group II (88 +/- 10%; p less than .01) and collateral filling of the LAD in no group I patient but in six of nine patients in group II (p less than .01). During LAD occlusion, determinants of myocardial oxygen demand (left ventricular filling pressure, aortic pressure, heart rate, and double product) were similar in both groups. Group I patients, however, had lower distal coronary pressure (25 +/- 8 vs 41 +/- 16 mm Hg) and residual great cardiac vein flow (33 +/- 14 vs 51 +/- 22 ml/min) and higher coronary collateral resistance (3.1 +/- 2.1 vs 1.5 +/- 0.8 mm Hg/ml/min) than group II patients (all p less than .05). In patients with ST elevation during LAD occlusion, stenosis before PTCA was less severe, visible collaterals were not present, and hemodynamic variables during LAD occlusion reflected poorer collateral function.(ABSTRACT TRUNCATED AT 250 WORDS)     

Coronary wedge pressure: a predictor of restenosis after coronary balloon angioplasty

Coronary wedge pressure is the pressure recorded distal to a stenosis while the inflated balloon occludes the coronary artery during angioplasty. This pressure has been shown to reflect actual (visible) and potential (recruitable) collateral flow to the stenosed artery, distal to the angioplasty site. In 100 consecutive vessels (91 patients) for which coronary wedge pressure had been measured at the time of angioplasty, the long-term (7 +/- 3 months) angiographic results was evaluated. The overall angiographic restenosis rate was 37%. It was 52% (25 of 48) in arteries with a coronary wedge pressure greater than or equal to 30 mm Hg and 23% (12 of 52) in arteries with a coronary wedge pressure less than 30 mm Hg (p less than 0.01). The mean coronary wedge pressure was 30 +/- 10 mm Hg for vessels with restenosis and 26 +/- 9 mm Hg for those without restenosis (p less than 0.01). The prevalence of angiographically visible collateral flow was 42% and 29%, respectively (p = NS). Neither age, sex, presence of unstable angina, left ventricular function, number of diseased vessels nor initial and final transstenotic pressure gradient and degree of stenosis were significantly associated with the long-term outcome after angioplasty. Restenosis rate is significantly increased when coronary wedge pressure measured at the time of angioplasty is high (greater than or equal to 30 mm Hg). This suggests a negative influence of competitive collateral flow on long-term results of angioplasty.     

The efficacy of intermittent coronary sinus occlusion in the absence of coronary artery collaterals

The purpose of this study was to evaluate the efficacy of time-controlled intermittent coronary sinus occlusion (ICSO) in preserving regional and global mechanical function during acute ischemia in an animal preparation without significant arterial collateral vessels. Seventeen (eight control, nine ICSO) swine heart preparations undergoing extracorporeal coronary perfusion in situ were subjected to ligation of the left anterior descending coronary artery (LAD) distal to the first major diagonal branch. Data were obtained before and immediately after coronary artery ligation in both animal groups. ICSO, 15 sec of occlusion alternating with 5 sec of release, was then begun in the treatment group. Additional data were obtained in both control and treatment groups at 15 min intervals for 1 hr starting immediately after coronary artery ligation. Global left ventricular function was assessed by shifts in left ventricular end-diastolic pressure and left ventricular dP/dt with left ventricular systolic pressure maintained at about 100 mm Hg. Regional mechanical function was evaluated with transmurally placed ultrasonic crystals. Pressure was also measured directly in the coronary sinus and LAD distal to the ligature. Regional myocardial blood flow was measured in the ischemic bed using 9 micron diameter radiolabeled microspheres injected before, immediately after, and 60 min after coronary artery ligation in both treated and control animals. LAD mean pressure measured distal to the ligation (less than 16 mm Hg) and ischemic bed myocardial blood flow (less than 0.01 ml/g/min) confirmed the absence of significant arterial-arterial collaterals in this preparation. Mean coronary sinus pressure increased significantly (p less than .001) in treated animals during ICSO (e.g., 11.2 +/- 1.6 to 66.2 +/- 10.0 mm Hg at 15 min after coronary ligation). Mean LAD pressure distal to the coronary ligature also increased during ICSO (14.2 +/- 1.2 to 26.8 +/- 1.6 mm Hg), with a similar but delayed rate of pressure rise. No significant differences in left ventricular end-diastolic pressure or left ventricular dP/dt were noted between control or treated animals after coronary ligation. Ischemic bed systolic wall thickening, present before coronary ligation, was not present after occlusion and was not improved during intermittent coronary sinus occlusion in the treatment group. We conclude that in an animal preparation without significant collateral circulation, intermittent coronary sinus occlusion is incapable of restoring regional or global left ventricular mechanical function during conditions of acute ischemia.     

Functional significance of coronary collateral vessels during exercise evaluated by radionuclide angiocardiography: the importance of supplying arteries

To investigate the function of coronary collateral vessels, especially from view point of supplying arteries, radionuclide angiocardiography was performed before and during a symptom-limited ergometer exercise in 54 patients with effort angina. In single vessel disease, during exercise, left ventricular ejection fraction (EF) (%) increased in the cases with coronary collateral vessels (supplied from patent arteries) (72 +/- 7----77 +/- 8, p less than 0.025), but decreased in those without (66 +/- 10----61 +/- 10, P less than 0.001). In multivessel disease, EF decreased during exercise even in those with collaterals (supplied from stenosed arteries) (67 +/- 10----59 +/- 8, p less than 0.001). It is concluded that angiographic appearance of the coronary arteries supplying collateral vessels is a major predictive factor of the function of coronary collateral vessels and of left ventricle during exercise.     

Functional significance of transient collaterals during coronary artery spasm

Coronary collateral vessels appear transiently during vasospasm. To examine the functional role of such collaterals in acute myocardial ischemia, regional coronary flow was determined in patients who showed isolated total spasm in the proximal left anterior descending coronary artery associated with (n = 7, group I) and without (n = 9, group II) collaterals, which were donated by the nonspastic right coronary artery during ergonovine provocative test. Aortic pressure and heart rate were not significantly different in the 2 groups before and during spasm. During vasospasm, the levels of pulmonary artery end-diastolic pressure were significantly higher in group II (19 +/- 2 mm Hg, mean +/- standard error) than in group I (15 +/- 1 mm Hg, p less than 0.05). Under these conditions, great cardiac vein flow (GCVF) measured by thermodilution was markedly reduced in group II (from 60 +/- 4 ml/min to 37 +/- 4 ml/min, p less than 0.01), whereas GCVF was slightly reduced in group I (from 56 +/- 4 ml/min to 51 +/- 4 ml/min), indicating that residual GCVF was greater in patients with than in those without collaterals (p less than 0.05). The calculated coronary collateral resistance index during vasospasm was significantly lower in group I (2.06 +/- 0.18 mm Hg min/ml) than in group II (2.91 +/- 0.30 mm Hg min/ml, p less than 0.05). Total left anterior descending coronary artery spasm with collaterals was less frequently associated with ST elevation in the precordial electrocardiogram recorded during spasm.(ABSTRACT TRUNCATED AT 250 WORDS)     

Left atrial function in acute transient left ventricular ischemia produced during percutaneous transluminal coronary angioplasty of the left anterior descending coronary artery

Left atrial (LA) function was studied in 32 patients during percutaneous transluminal coronary angioplasty of the proximal left anterior descending artery with a dual micromanometer positioned transseptally in the left atrium and in the left ventricle. In 10 patients LA and left ventricular (LV) cineangiography was performed 30 minutes before percutaneous transluminal coronary angioplasty and 30 seconds after the occlusion of the left anterior descending coronary artery. Thirty seconds after left anterior descending occlusion, LV peak systolic pressure decreased from 135 +/- 12 to 106 +/- 9 mm Hg (p less than 0.05) and LV maximum dP/dt decreased from 1,634 +/- 136 to 1,137 +/- 127 mm Hg/s (p less than 0.01). Simultaneously, LA mean pressure increased from 11 +/- 2 to 29 +/- 1 mm Hg (p 177 +/- 13 to 381 +/- 21 mm Hg (p less than 0.001). There was a difference between LV end-diastolic pressure and LA mean pressure of 1.5 mm Hg at rest and 7.8 mm Hg during ischemia and LA pulse pressure increased from 16 +/- 3 to 26 +/- 3 mm Hg (p less than 0.05) together with increase of LA A and V waves peak pressure. LV stroke volume index decreased from 46 +/- 5 to 43 +/- 3 ml/m2 (difference not significant). The LA maximal volume increased from 18 +/- 2 to 29 +/- 3 ml/m2 (p less than 0.001). LA volume before LA contraction increased from 29 +/- 2 to 54 +/- 3 ml/m2 (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of aging on pulmonary hemodynamics in a population free of coronary artery disease

Previous studies showing an increase in pulmonary artery (PA) pressures and vascular resistance with aging have not systematically excluded subjects with coronary artery disease or left ventricular systolic dysfunction. To better determine the influence of aging on PA hemodynamics in the absence of disease, we identified 47 normal subjects angiographically free of coronary artery disease (18 men, 29 women) with normal left ventricular systolic function (ejection fraction greater than or equal to 50% and left ventricular end-diastolic pressure less than 14 mm Hg) from 5,508 consecutive patients undergoing cardiac catheterization and coronary angiography between September 10, 1982 and March 9, 1987. All subjects met a set of clinical and laboratory criteria identifying them as normal. In group I (age greater than or equal to 60 years) mean PA pressure was 16 +/- 3 mm Hg, pulmonary vascular resistance was 124 +/- 32 dynes s cm-5 and the pulmonary/systemic vascular resistance ratio was 0.099 +/- 0.046. In contrast, in group II (age less than 60 years), these values were lower at 12 +/- 2 mm Hg, 70 +/- 25 dynes s cm-5 and 0.057 +/- 0.019, respectively (all p values less than 0.01 to 0.001). All these parameters increased linearly with age (r = 0.69, p less than 0.001 for pulmonary vascular resistance). The differences were not attributable to body surface area or gender. There was no difference in cardiac output, PA wedge pressure, aortic pressure or systemic vascular resistance between the 2 groups. Thus, PA pressure and vascular resistance increase with aging, a change not attributable to coronary disease or left ventricular systolic dysfunction.     

Evaluation of coronary collateral circulation in conscious humans

The physiologic importance of coronary collateral vessels was investigated in 19 men undergoing transient proximal occlusion of the left anterior descending (LAD) branch without sedative medication. No vasodilators were given before LAD balloon occlusion. Six men had angiographic filling of the LAD via coronary collateral vessels (Group 1) and 13 did not (Group 2). Aortic, distal coronary and left ventricular (LV) filling pressures and great cardiac vein blood flow (thermodilution) were recorded continuously during occlusion. During LAD occlusion, clinical and electrocardiographic evidence for transient myocardial ischemia occurred more often in patients in Group 2 than in Group 1, but the difference was not statistically significant. Heart rate and aortic and distal coronary pressures were similar in Groups 1 and 2. LV filling pressure was 3 mm Hg higher in Group 2 patients (p less than 0.05). The aortic to distal coronary pressure difference and the distal coronary to LV filling pressure difference were also similar in Groups 1 and 2. However, residual great cardiac vein flow was 55% higher (p less than 0.05) and the calculated coronary collateral resistance index was 45% lower in patients in Group 2 compared with those in Group 1 (p less than 0.01). Coupling of regional coronary venous blood flow estimates to pressure measurements routinely made during angioplasty is a new technique that allows evaluation of determinants of coronary collateral function in conscious humans.(ABSTRACT TRUNCATED AT 250 WORDS)     

Collateral conductance changes during a brief coronary occlusion in awake dogs

Function of the coronary collateral circulation during the course of a single abrupt coronary occlusion was evaluated in awake dogs instrumented over the long term. Studies were performed approximately 2 weeks after collateral development had been stimulated in the dogs by partial stenosis of the proximal left circumflex coronary artery. The pressure drop from the central aorta to the distal circumflex coronary artery was measured continuously. Under control conditions and at 30 sec and 4 min of a single abrupt complete circumflex occlusion, myocardial blood flow was determined by a radioactive microsphere technique. Coronary collateral conductance was calculated as mean collateral blood flow divided by the mean drop in pressure. The following was noted in dogs that developed collateral vessels: during the coronary occlusion, mean distal circumflex coronary pressure increased from 42 +/- 9 to 49 +/- 10 mm Hg (p less than or equal to .01); mean collateral flow increased from 0.78 +/- 0.30 to 0.84 +/- 0.33 ml/min/g (p less than or equal to .05); the endocardial/epicardial flow ratio increased from 0.77 +/- 0.36 to 1.04 +/- 0.25 (p less than or equal to .01); and the coronary collateral conductance increased significantly from 0.017 +/- 0.017 to 0.021 +/- 0.021 (ml/min/g)/mm Hg (p less than or equal to .005). These data suggest that during a brief occlusion of a major coronary artery, immature coronary collateral channels do not reach maximal function immediately after the occlusion. Rather, coronary collateral conductance increases with time and may be associated with improved transmural perfusion of the myocardium.     

ST monitoring for myocardial ischemia during and after coronary angioplasty

We performed 12-lead electrocardiographic monitoring in 97 patients during coronary angioplasty (PTCA) of a single vessel to correlate ischemic ST changes with clinical, angiographic and coronary hemodynamic variables and to determine the optimum lead or combination of leads for their detection. Ischemia (chest pain or ST change, group A) occurred in 79 patients (80%), but in only 15 of 23 patients (65%) with collaterals (p less than 0.05). Ischemia occurred more often in left anterior descending and left circumflex PTCA than right coronary PTCA, but pain was the only manifestation more often in left circumflex and right coronary PTCA. Ischemic ST change was silent in 16% and this proportion did not differ in clinical or angiographic groups except for diabetes with 3 of 5 (60%) having silent ischemia (p less than 0.05). Patients in group A (ischemia) compared to group B (no ischemia) had less severe lesions (85 +/- 9 vs 91 +/- 7%, p less than 0.01), higher transstenotic gradients (62 +/- 19 vs 53 +/- 9 mm Hg, p less than 0.05) and lower distal occluded pressures (24 +/- 11 vs 33 +/- 10 mm Hg, p less than 0.01), suggesting less collateral flow. Compared with a 12-lead electrocardiogram, the best single lead for detecting ST change during PTCA in each artery had a sensitivity of 80% and this increased to 93% using the best 2 leads. The best 3 leads (V3/III/V5 for left anterior descending and III/V2/V5 for right coronary and left circumflex) increased sensitivity to 100%.(ABSTRACT TRUNCATED AT 250 WORDS)     

Differential effects on right ventricular function of transient right, left anterior descending and left circumflex coronary occlusions during percutaneous transluminal coronary angioplasty

Right ventricular function was studied by means of a thermodilution catheter before, during and after percutaneous transluminal angioplasty of the proximal right (group 1, n = 8), left anterior descending (group 2, n = 8) or left circumflex (group 3, n = 8) coronary artery. All patients had evidence of myocardial ischemia, with single-vessel disease affecting the proximal segment of one of the three major coronary arteries; no patient had had a previous myocardial infarction and all had normal cardiac function at baseline study. Cardiac index decreased during balloon inflation. Mean pulmonary artery pressure was unaffected in group 1 but increased in group 2 (from 19 +/- 5 to 31 +/- 11 mm Hg, p less than 0.01) and in group 3 (from 19 +/- 2 to 22 +/- 5 mm Hg, p less than 0.05). Right ventricular ejection fraction decreased from 62 +/- 9% to 52 +/- 10% (p less than 0.01) in group 1 and from 64 +/- 7% to 44 +/- 10% (p less than 0.005) in group 2, and returned to normal within 2 min after balloon deflation in both groups. In group 3, right ventricular ejection fraction was unchanged during balloon inflation (58 +/- 5% at baseline, 58 +/- 9% at 60 s, p = NS). Therefore, brief occlusion of the proximal segments of the left anterior descending or right coronary artery results in marked alteration of right ventricular performance that is probably caused by right ventricular free wall ischemia in the right coronary group and by the concomitant effects of septal ischemia and increased right ventricular afterload in the left anterior descending artery group.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of minimal angiographic visible collateral circulation on myocardial function during PTCA.

The potential protective role of angiographically visible minimal collateral circulation in diagnostic angiograms, not reaching or filling the target vessel (RENTROP class 1), on myocardial function during percutaneous transluminal coronary angioplasty (PTCA), was studied in two groups of patients undergoing elective PTCA of the left anterior descending artery (LAD). In the first study group consisting of 22 patients, influence of collateral circulation class 1 on left ventricular regional function was evaluated. In this group, 14 patients showed no angiographic collaterals and 8 patients showed collateral circulation class 1 in diagnostic angiograms. Increase of end-diastolic and end-systolic volume indices as well as decrease of global left ventricular function was not significantly different inpatients with and without such minimal collateral circulation. In patients without collaterals, the decrease of regional left ventricular function was significantly more pronounced in the left anterior length segment (p less than 0.05) and a trend was observed in the anterolateral (p = 0.059) and apical (p = 0.053) segments. In a second group, consisting of 29 patients, hemodynamic parameters were measured and, in addition to grading of collateral circulation in diagnostic angiograms, angiographically visible collateral circulation was estimated during occlusion of the LAD by injecting contrast materials into the right coronary artery. An increase of angiographically visible collaterals during the ischemic period of various degrees was documented in 26 (90%) of 29 patients. Combining patients of both study groups, increase in left ventricular end-diastolic pressure during ischemia was significantly higher (p less than 0.05) in patients without collaterals on diagnostic angiography (n = 34) than in patients with collateral circulation class 1 (n = 14).(ABSTRACT TRUNCATED AT 250 WORDS)     

Augmentation of regional function in nonischemic myocardium during coronary occlusion measured with two-dimensional echocardiography

Increased regional left ventricular function frequently occurs in the nonischemic myocardium after acute coronary occlusion. To further define the regional and global effects of this increased remote function in the ischemic left ventricle, 22 dogs were studied with two-dimensional echocardiography before and 1 h after left circumflex coronary artery occlusion. Two groups of dogs were identified with and without compensatory increased regional left ventricular function, defined as regional wall thickening in the nonischemic zone greater than 2 SD above baseline. After coronary occlusion, nonischemic wall thickening was 76 +/- 15% in the hyperfunction group (n = 11) and 45 +/- 14% in the nonhyperfunction group (n = 11) (p less than 0.001). Despite similar left ventricular end-diastolic cavity areas and equivalent degrees of ischemic wall thinning, dogs with increased left ventricular function in the nonischemic myocardium had a smaller extent of circumferential left ventricular dysfunction (136 +/- 33 versus 170 +/- 43 degrees, p less than 0.001) and a higher area ejection fraction (38 +/- 9% versus 27 +/- 6%, p less than 0.001). These functional differences occurred despite similar myocardial areas at risk by autoradiography (41 +/- 6% versus 37 +/- 12%, p = NS). The data suggest that increased left ventricular function in the nonischemic myocardium determines the global functional impact of acute coronary occlusion and, through interaction with adjacent myocardium, modifies the extent of circumferential left ventricular dysfunction.     

Functional importance of coronary collateral vessels

Angiographically demonstrable coronary collateral vessels are believed to preserve myocardial function at rest, but disagreement exists regarding the importance of collaterals in mitigating exercise-induced ischemic dysfunction. Therefore, we used radionuclide cineangiography during exercise to assess the left ventricular (LV) functional effects of collateral vessels in 125 patients with at least 1 major coronary artery that had greater than or equal to 90% diameter stenosis but without prior myocardial infarction. Regional LV function, graded on a 4-point scale, worsened during exercise by at least 1 grade in 14 of 43 regions (33%) with good collaterals, and in 70 of 98 without good collaterals (p less than 0.001). Of the 43 good collaterals, 14 were supplied by arteries with greater than or equal to 75% stenoses; 10 of 14 regions (71%) thus supplied worsened by at least 1 grade (p less than 0.01). The ischemia-mitigating effect of coronary collateral vessels also affected the magnitude of exercise-induced global dysfunction. Of 43 patients with only one greater than or equal to 90% stenotic artery, 18 had good collaterals; in these patients, average LV ejection fraction (EF) at rest was 51 +/- 8%; LVEF during exercise was 46 +/- 7%. In the 25 patients without good collaterals, LVEF at rest was 52 +/- 7%, and LVEF during exercise was 41 +/- 9% (p less than 0.005 vs good collaterals).(ABSTRACT TRUNCATED AT 250 WORDS)     

Coronary collateral circulation in coronary artery disease and systemic hypertension

The extent and functional capacity of coronary collateral circulation in patients with systemic hypertension has not been elucidated. In the present study, 313 patients with coronary artery disease were studied to evaluate coronary collateral circulation in relation to the presence of systemic hypertension and left ventricular hypertrophy. Patients had greater than or equal to 95% diameter luminal obstruction of either the left anterior descending or the right coronary artery. Patients were classified into 2 groups: The hypertensive group consisted of 61 patients, mean age 55 +/- 9 years, with systemic hypertension, and the normotensive group consisted of 252 patients, mean age 53 +/- 8 years, without hypertension. The hypertensive group had more severe angina pectoris and less history of healed myocardial infarction than the normotensive group (p less than 0.001). Left ventricular wall thickness was 1.26 +/- 0.1 cm in the hypertensive and 1.03 +/- 0.06 cm in the normotensive group (p less than 0.001). The hypertensive group had more extensive coronary collateral circulation than the normotensive group (p less than 0.01). There was a positive relation between coronary collateral circulation and left ventricular wall thickness (p less than 0.001). These results indicate that patients with systemic hypertension and coronary artery disease have an increase in coronary collateral circulation corresponding to the degree of left ventricular wall thickness.     

Early changes in ventricular function in diastolic phase in the resting coronary patient

The aim of this study is to test left ventricular diastolic function in coronary artery disease patients with preserved systolic performance. Two groups of patients (25 coronary artery disease patients with angiographic proved coronary artery stenosis, but with normal hemodynamic and angiographic indices of systolic phase, first group; and 14 normal subjects for control, second group) were tested comparing their systolic and diastolic ventricular function indices, obtained by using a Millar microtip catheter and a computerized program. Systolic ventricular function was similar in the two groups (EF: 0.61 +/- 0.05 vs 0.62 +/- 0.03, p: n.s.; Vmax:120 +/- 28 vs 112 +/- 24 sec-1, p: n.s.), while diastolic indices were significantly different (lowest diastolic pressure: 3.7 +/- 2.4 vs -1.72 +/- 1.45 mmHg, p less than 0.01; end-diastolic pressure: 11.2 +/- 4.2 vs 6.5 +/- 2.8 mmHg, p less than 0.05; T constant: 45 +/- 8 vs 35 +/- 6 mmHg, p less than 0.001; end-diastolic compliance: 2.79 +/- 0.3 X 10(-2) vs 5.68 +/- 0.4 X 10(-2) mmHg-1, p less than 0.001; Kp: 0.041 +/- 0.006 vs 0.003 +/- 0.004 p less than 0.001). In conclusion, impairment of left ventricular diastolic phase may be one of the earliest manifestations of functional alterations of ischemic ventricle.     

Hemodynamic and echocardiographic assessment of the effects of diltiazem during transient occlusion of the left anterior descending coronary artery during percutaneous transluminal coronary angioplasty

The effects of diltiazem during transient myocardial ischemia were studied in 17 patients (age 58 +/- 11 years, 12 men, 5 women) undergoing 1-vessel left anterior descending percutaneous transluminal coronary angioplasty (PTCA). After hemodynamic, echocardiographic and electrocardiographic data were obtained during the control ischemic periods, diltiazem (10 mg intravenous bolus with 500 micrograms/min infusion) was given and 15 minutes later ischemia reinduced. Diltiazem reduced mean arterial pressure (113 +/- 16 to 95 +/- 15 mm Hg, p less than 0.05) and heart rate-pressure product (p less than 0.05) with no change in heart rate, pulmonary pressures or coronary (sinus, thermodilution technique) blood flow at rest. After diltiazem, times to ischemia-induced 1.0 mm ST-segment elevation (28 +/- 10 to 42 +/- 17 seconds, p less than 0.05) and new left ventricular wall motion abnormalities (by 2-dimensional echocardiography, 24 +/- 8 to 36 +/- 12 seconds, p less than 0.001) were prolonged without significant augmentation of great cardiac vein flow during coronary occlusion. Left ventricular (LV) ejection fraction decreased from 51 +/- 7 to 41 +/- 12% (p less than 0.05) during control ischemia, but declined less after diltiazem (54 +/- 12 to 47 +/- 14%, difference not significant; 47 +/- 14 vs 41 +/- 12%, p less than 0.01). Diltiazem can attenuate, but not abolish, some of the effects of myocardial ischemia on LV function during transient coronary artery occlusion. These data support the use of diltiazem as a beneficial adjunct that may be used acutely and safely during routine PTCA.     

Coronary artery cardiomyopathy. Hemodynamic and prognostic implications

To assess the prevalence and significance of left ventricular dilatation in patients with severe left ventricular dysfunction secondary to coronary artery disease (or coronary artery cardiomyopathy), we studied 70 patients with an ejection fraction of 35 percent or less and one-vessel coronary artery disease (n = 14) or with multivessel coronary artery disease (n = 56). None had had a recent myocardial infarction or valvular heart disease. Patients who underwent myocardial revascularization during follow-up were excluded. The left ventricular end-diastolic volume (measured by contrast ventriculography) was less than 110 ml/sq m in 14 patients (20 percent) (group 1), and was 110 ml/sq m or more in 56 patients (80 percent) (group 2). There were no differences between the two groups in age, sex, diabetes mellitus, hypertension, extent of coronary artery disease, or left ventricular asynergy. Patients in group 1 had lower pulmonary arterial wedge pressure (13 +/- 6 vs 22 +/- 10 mm Hg; p = 0.0008), lower left ventricular end-diastolic pressure (21 +/- 6 vs 27 +/- 9 mm Hg; p = 0.007), and higher left ventricular ejection fraction (31 +/- 2 vs 25 +/- 7 percent; p = 0.001) than patients in group 2. At a mean follow-up of 27 months, 24 patients had died of cardiac causes, all of whom were in group 2. Survival was significantly better in group 1 than in group 2 (Mantel-Cox, p = 0.009). Survival analysis (Cox models) of 20 clinical, hemodynamic, and angiographic variables showed that ejection fraction (chi2 = 13.6; p less than 0.001) and end-diastolic volume chi2 = 4.7; p = 0.03) were the most significant predictors of death. Thus, minimally dilated coronary artery cardiomyopathy is a distinct entity with favorable hemodynamics. Prognostically, the end-diastolic volume adds significant predictive information to the ejection fraction among conservatively treated patients.     

Effect of acute short-term ischemia during PTCA on the function of the right ventricle

To determine whether a transient ischemia of the right ventricle leads to right ventricular impairment and whether RV function can also be influenced by septal ischemia caused by an occlusion of the left anterior descending coronary artery (LAD), RV function before and at the end of 60 s of ischemia during PTCA was assessed in 15 patients with single-vessel disease of either the right coronary artery (RCA, n = 10) or the LAD (n = 5). The RV-enddiastolic pressure and the pulmonary capillary wedge pressure (PCW) were recorded continuously. The RV ejection fraction was determined from ventriculograms performed before and during coronary occlusion. An increase of RVEDP from 3.7 +/- 1.2 to 8.3 +/- 1.8 mm Hg (p less than or equal to 0.001) and a decrease of the RV-ejection fraction from 52 +/- 3 to 33 +/- 8% (p less than or equal to 0.001) occurred during RCA occlusion with a predominant ischemia of the RV free wall only, and not during LAD occlusion with left ventricular and septal ischemia. The extent of the RV dysfunction was independent of an additional increase of RV afterload (PCW increase). Comparable to ischemic effects on left ventricular function, an acute right ventricular myocardial ischemia results in a severe RV contractile failure.     

The resolution of coronary collaterals after successful percutaneous transluminal coronary angioplasty

It has been shown that collaterals can develop rapidly during acute coronary occlusion, either due to thrombosis or during angioplasty (PTCA). However, the fate of well-developed collaterals immediately after a successful PTCA is unknown. Accordingly, 15 patients with Rentrop class 2 or 3 collaterals as visualized angiographically were studied immediately after successful single-vessel PTCA. The left anterior descending artery contained the stenosis in nine patients and the right coronary contained the stenosis in six patients. There was total occlusion of six vessels and subtotal occlusions of nine vessels pre PTCA. Immediately after PTCA, flow through the collaterals to the stenosed artery could no longer be visualized angiographically in eight patients (group 1), but remained faintly visible in seven patients (group 2). There was no difference between these two groups with regard to pre PTCA transstenotic pressure gradient (46 +/- 12 vs 42 +/- 14 mm Hg), post PTCA pressure gradient (13 +/- 7 vs 11 +/- 10 mm Hg), or post PTCA percent luminal diameter narrowing (26 +/- 18% vs 24 +/- 13%). These findings suggest that despite similar hemodynamic and angiographic improvement, the resolution of collaterals immediately after PTCA is variable.