Effect of right coronary artery occlusion during percutaneous transluminal coronary angioplasty on right ventricular performance

Role of the etiology of cardiomyopathies on exercise capacity and oxygen consumption in patients with severe congestive heart failure

Peak oxygen consumption is of great importance for the decision of heart transplantation in congestive heart failure. Moreover, the level of exercise capacity seems to depend on the etiology of congestive heart failure. This study compared 14 heart failure patients with idiopathic dilated cardiomyopathy (group 1) to 14 heart failure patients with cardiomyopathy due to ischemic heart disease (group 2), matched for sex (13 male, one female in each group), age +/-10 years, left ventricular ejection fraction +/-5% and pulmonary artery mean pressure +/-5 mm Hg, to assess exercise capacity and oxygen consumption independently of the age, sex and the level of left ventricular dysfunction. Right ventricular function was also assessed. No difference existed in terms of right ventricular parameters. Maximal exercise parameters were significantly higher in group 1 than in group 2. Peak oxygen consumption was statistically higher in group 1 than in group 2. In the whole population, a significant correlation was found between peak oxygen consumption and right ventricular ejection fraction (r=0. 44, P<0.02) but not between peak oxygen consumption and left ventricular ejection fraction. For similar levels of left ventricular dysfunction, exercise capacity and oxygen consumption appear to be better in idiopathic dilated cardiomyopathy than in ischemic cardiomyopathy, thereby suggesting that functional tolerance of left ventricular dysfunction might depend on the etiology of severe congestive heart failure.

Right ventricular dysfunction during coronary artery occlusion: pressure-volume analysis using conductance catheters during coronary angioplasty

OBJECTIVE

To study the effects of coronary artery occlusion on the pressure-volume relations of the right ventricle.

DESIGN

Right ventricular pressure-volume cycles were studied using conductance catheters and micromanometers in 19 subjects undergoing coronary angioplasty in a tertiary referral cardiac centre.

RESULTS

Catheter occlusions of either the left anterior descending coronary artery or the right coronary artery were associated with a decline in stroke work (mean change (SD): left-13.3 (15.8)%, p = 0.008; right -13.5(16.5)%, p = 0.04). Two patterns of change were evident: an upward shift usually associated with occlusion in the left coronary artery, and a rightward shift in the right coronary artery. In the former there was an increase in maximum ventricular volume (mean change: 3.0(2.7)%, p = 0.004) and in minimum ventricular volume (mean change: 2.3(2.7)%, p = 0.01) and a fall in peak pressure (mean change: -4.8 (5.1)%, p = 0.04). In the latter there was an increase in peak pressure (mean change 9.9(16.3)%, p = 0.04) and an increase in minimum ventricular volume (mean change 3.7(5.0)%, p = 0.02) leading to a fall in stroke volume (mean change -13.3(15.8)%, p = 0.008).

CONCLUSIONS

Occlusion of the left anterior descending coronary artery or the right coronary artery is associated with a decline in right ventricular work. However, different patterns of change in indices of preload and afterload lead to different effects on overall right ventricular pump function.

Influence of exercise induced myocardial ischemia on right ventricular dP/dt: potential implications for rate responsive pacing

BACKGROUND

Right ventricular (RV) dP/dtmax has been used as a simple parameter for rate responsive pacing to simulate the normal sinus node function. However, the effect of acute myocardial ischemia on RV dP/dtmax has not yet been evaluated.

METHODS

RV high fidelity pressure was measured in 21 patients at rest and during supine bicycle exercise. Nine patients (Group 1 = controls) had no or only minimal alterations of the coronary arteries and 12 (Group 2 = CAD) had significant coronary artery disease with exercise induced left ventricular (LV) wall-motion abnormalities (n = 10) and/or angina pectoris (n = 6). RV pressure and its first derivative (RV dP/dt) were determined by an 8 French micromanometer catheter. The time constant of RV pressure decay (Tau) was calculated from the negative reciprocal of RV pressure versus negative dP/dt during isovolumic relaxation. RV volumes and ejection fraction were calculated from RV biplane angiograms (multiple slice method) at rest and during exercise.

RESULTS

Heart rate (HR), RV dP/dtmax and dP/dtmin increased significantly during exercise, whereas Tau decreased. There were no significant differences between the two groups, although RV ejection fraction increased from 67% to 72% in the control group but decreased from 63% to 51% in the CAD group (P < 0.05). An exponential relationship was found between HR and dP/dtmax with a correlation coefficient of 0.82 (P < 0.01; SEE = 7% of the mean value).

CONCLUSIONS

Acute exercise induced myocardial ischemia does not significantly influence RV dP/dtmax during sinus rhythm. Consequently, this index of RV contractility may be used in patients with coronary artery disease as a simple parameter for rate responsive pacing.

Beneficial cumulative role of both nitroglycerin and dobutamine on right ventricular systolic function in congestive heart failure patients awaiting heart transplantation

End-stage idiopathic dilated cardiomyopathy or ischemic heart disease usually present with very low cardiac output and severe ventricular dysfunction which may require pharmacological support before heart transplantation. Right ventricular ejection fraction might be an important factor of functional capacity and survival in congestive heart failure. In order to test the immediate response of right ventricular hemodynamic parameters to nitroglycerin and dobutamine usually used to treat severe left ventricular dysfunction, we studied 17 congestive heart failure patients (15 men, two women; mean age 55 +/- 13 years) with end-stage idiopathic dilated cardiomyopathy (n = 10) or end-stage ischemic heart disease (n = 7), left ventricular ejection fraction < 35% (mean 22 +/- 8%), and sinus rhythm. A well validated thermodilution technique using a dedicated catheter with a fast catheter-computer response, permitting instantaneous measurements of right ventricular ejection fraction, was used. Right ventricular hemodynamic parameters were recorded at baseline, after an intravenous bolus injection of 3 mg nitroglycerin and after an intravenous infusion of dobutamine administered after nitroglycerin until normalization of cardiac index or a maximal dose of 15 micrograms/kg/min. Pulmonary artery mean pressure significantly decreased after nitroglycerin (43 +/- 9 mmHg at baseline vs. 31 +/- 10 mmHg after nitroglycerin, P < 0.0001) and did not subsequently change after dobutamine (32 +/- 10 mmHg after dobutamine, ns). Cardiac index was not affected by nitroglycerin (1.7 +/- 0. l/min/m2 at baseline vs. 2.0 +/- 0.3 l/min/m2 after nitroglycerin, ns), but dramatically increased after dobutamine (3.0 +/- 1.0 l/min/m2 after dobutamine, P < 0.0001). Concomitantly to the changes of these two parameters, right ventricular ejection fraction progressively increased (14 +/- 8% at baseline vs. 20 +/- 10% after nitroglycerin (P < 0.0006) vs. 28 +/- 13% after dobutamine (P < 0.0001)). Progressive increase of right ventricular ejection fraction after administration of nitroglycerin followed by administration of dobutamine suggests the beneficial cumulative role of both medications on right ventricular systolic function in severe congestive heart failure.

Comparison of right ventricular systolic function in idiopathic dilated cardiomyopathy and healed anterior wall myocardial infarction associated with atherosclerotic coronary artery disease

A case-controlled study assessed right ventricular (RV) systolic function in 10 patients with idiopathic dilated cardiomyopathy (IDC) and in 10 with healed anterior wall myocardial infarction associated with atherosclerotic coronary artery disease (CAD). Each patient was matched for sex, left ventricular ejection fraction +/- 5% and pulmonary artery mean pressure +/- 5 mm Hg. All patients had sinus rhythm and a left ventricular ejection fraction < 45%. A new, well-validated thermodilution technique was used to assess RV ejection fraction and volumes. RV ejection fraction was lower in the IDC than in the CAD group (25 +/- 14% vs 36 +/- 11%; p < 0.02). Linear correlations between RV parameters and pulmonary artery pressure were significantly present in both groups. However, the slopes of the equations were not statistically different. In comparison with healed anterior wall myocardial infarction with CAD and for similar levels of left ventricular dysfunction, RV systolic function appeared to be more altered in IDC.

Right ventricular ejection fraction during exercise in patients with recent myocardial infarction: effect of the interventricular septum

To investigate the effect of interventricular septum (IVS) on right ventricular function during exercise, radionuclide angiocardiography was performed in 50 patients with recent myocardial infarction. Twenty-five patients had involvement of IVS according to thallium uptake in IVS (group I), and 25 patients were free of IVS involvement (group II). Although there was no statistical difference between the two groups in right ventricular ejection fraction (EF) at rest (45% +/- 10% vs 48% +/- 8%), patients in group I had significantly lower left ventricular (LV) EF (40% +/- 11% vs 53% +/- 11%, p < 0.01) and larger LV end-diastolic volume (129 +/- 46 vs 106 +/- 31 ml, p < 0.05) than those in group II. All parameters increased significantly during exercise in both groups, but patients in group I had significantly lower exercise right ventricular EF (50% +/- 10% vs 56% +/- 9%, p < 0.05), LVEF (44% +/- 11% vs 56% +/- 13%, p < 0.01), and larger LV end-diastolic volume (155 +/- 44 vs 129 +/- 37 ml, p < 0.05) than those of group II. Significant correlations were observed between right ventricular EF and LV end-diastolic volume at rest and during exercise (r = -0.48, p < 0.05, and r = -0.68, p < 0.01, respectively) in group I, but right ventricular EF correlated with LVEF only at peak exercise (r = 0.65, p < 0.01). In contrast, right ventricular EF did not correlate with any variables at rest or during exercise in group II.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary artery hemodynamic response to proximal balloon dilatation of a large dominant right coronary artery

The human right ventricle has a relatively low tolerance to even short periods of ischemia. During angioplasty of the right coronary artery, pulmonary artery pressure typically rises due to an increase in right ventricular afterload caused by left ventricular dysfunction during ischemia. We have presented two cases of angioplasty in the early proximal portion of a large, highly dominant right coronary artery. Pulmonary artery and systemic pressure fell during balloon inflation probably secondary to acute severe right ventricular failure, though an interaction with left ventricular dysfunction cannot be excluded. These observations do emphasize the hemodynamic and combined ventricular consequences of proximal angioplasty in a large, dominant right coronary artery, particularly in the setting of preexisting left ventricular dysfunction.

Effects of acute, transient coronary occlusion on global and regional right ventricular function in humans

OBJECTIVES

The aim of this study was to investigate the changes in right ventricular function during acute coronary occlusion produced by inflating a coronary angioplasty balloon catheter.

BACKGROUND

Alterations in right ventricular function are well known to occur in patients with acute myocardial infarction or ischemic cardiomyopathy. However, the changes in right ventricular function resulting from acute, transient coronary occlusion of each of the major coronary arteries have been scantily studied, perhaps because of serious limitations of currently available technology.

METHODS

A newly designed, mobile, multiwire gamma camera, in combination with generator-produced tantalum-178, affords high count rate first-pass radionuclide angiography and is thus ideal for studying right ventricular function at the bedside. Accordingly, 46 patients underwent first-pass radionuclide angiography at baseline and during transient coronary occlusion induced by a coronary angioplasty balloon catheter.

RESULTS

A significant, albeit modest, decrease in global right ventricular ejection fraction occurred during occlusion of the left anterior descending (from 42.9 +/- 9.3% to 39 +/- 8.7%, p < 0.05) and left circumflex (from 44 +/- 9.1% to 38.8 +/- 7.9%, p = 0.03) coronary arteries, but diagonal artery occlusion caused no significant change in right ventricular ejection fraction. Occlusion of the right coronary artery proximal (but not distal) to the acute marginal branch caused a significant decrease in right ventricular ejection fraction (from 42.6 +/- 4.7% to 35.7 +/- 7.2%, p < 0.01). Although occlusion of the left anterior descending, left circumflex and proximal right coronary arteries all caused significant deterioration in regional right ventricular function, only proximal right coronary occlusion caused right ventricular dilation (p < 0.005).

CONCLUSIONS

Significant impairment of right ventricular function occurs during transient occlusion of the left anterior descending, left circumflex and proximal right coronary arteries, but only occlusion of the latter causes acute right ventricular dilation, probably as a result of ischemia.

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)

Right ventricular systolic function during exercise with and without significant coronary artery disease

To evaluate the effects of exercise and coronary artery disease on right ventricular (RV) systolic function, rest and exercise biplane RV angiograms were recorded in 20 patients undergoing diagnostic cardiac catheterization. Thirteen patients had exercise angiograms of sufficient quality to undergo analysis and were classified into 2 groups. Group 1 had no or only mild coronary artery disease; group 2 had significant coronary artery disease as manifested by new, exercise-induced, left ventricular regional wall motion abnormalities. RV systolic pressure increased in both groups during exercise: 33 to 57 mm Hg in group 1 (p = 0.0002) and 33 to 55 mm Hg in group 2 (p = 0.0004). Pulmonary resistance did not change in group 1 during exercise but increased in group 2 (3.2 to 4.8 Wood units, p = 0.04). RV ejection fraction increased slightly, but not significantly, during exercise in group 1, but decreased in group 2 (73 vs 58% with exercise [p = 0.01]). The change in RV ejection fraction from rest to exercise correlated closely with the change in pulmonary resistance from rest to exercise (r = -0.89, p less than 0.0001). RV regional wall motion analysis demonstrated a generalized decline in regional ejection fraction in group 2 during exercise, even in patients without right coronary artery disease. In conclusion, there is a decline in RV ejection fraction during exercise in patients with significant coronary artery disease. The generalized reduction in regional RV ejection fraction coupled with the close correlation with the change in pulmonary resistance suggests that increased afterload, rather than RV ischemia, is the cause.

Right ventricular diastolic function during exercise: effect of ischemia

The effects of exercise on right ventricular diastolic function were evaluated in 14 patients who underwent supine rest and exercise right ventricular angiography. On the basis of coronary anatomy and exercise left ventricular regional wall motion analysis, these patients were classified into two groups: Group 1 (n = 7) had no or only mild coronary artery disease and Group 2 (n = 7) had significant coronary disease and exercise-induced left ventricular wall motion abnormalities suggesting ischemia. Chamber stiffness at rest was higher in Group 2 (48 x 10(-3) ml-1/m2) than in Group 1 (18 x 10(-3) ml-1/m2, p = 0.006). During exercise, right ventricular filling rate in the second half of diastole was significantly lower in Group 2 (126 versus 276 ml/m2 per s, p less than 0.03). The time constant of right ventricular pressure decay decreased significantly in both groups with exercise; however, both groups displayed a parallel upward shift of the pressure-volume curve with exercise. Because ischemia could not be demonstrated in Group 1, it is an unlikely explanation for this shift. Septal shifting was not a significant factor with exercise. Because of an increase in left ventricular end-diastolic volume with exercise and a close correlation between right and left ventricular end-diastolic pressures (r = 0.96 for Group 1 and r = 0.76 for Group 2), pericardial constraint is the most likely cause for this upward shift of the pressure-volume curve. Therefore, an increase in right ventricular end-diastolic pressure may not be a reliable indicator of ischemia during exercise because this pressure is coupled to changes in left ventricular volume and pericardial constraint.