Tift Mann

Contractile state of the left ventricle in man as evaluated from end-systolic pressure-volume relations.

End-systolic pressure (PE8), volume (VES), wall tension (TE8) and circumference (CES) of the human left ventricle were studied at cardiac catheterization in 24 subjects with varying degrees of left ventricular dysfunction. Acute alterations in systolic load consistently resulted in changes in VEs and CEs, with a smaller volume and circumference characterizing the lower systolic load in each subject. End systolic pressure-volume lines were constructed by plotting PEs against VEs at the higher and lower systolic load in each subject. The slope of the resultant lines was considerably steeper for normal than for poorly contractile left ventricles. V., the volume axis in- tercept of the line (i.e., the theoretical VES at PES = 0) was significantly smaller for normal than for poorly contractile ventricles. Similar findings were noted for C., the theoretic end-systolic circumference at zero end-systolic ventricular wall tension. Postextrasystolic potentiation resulted in decreased VES and Cg8 with no change in PES and only a slight fall in TE8. In conclusion, end-systolic pressure-volume and tension-circumference relations reflect the contractile state of left ventricular myocardium. Quantitation of these relationships may provide a useful new approach to the assessment of myocardial function in man.

Transradial Approach for Coronary Angiography and Interventions: Results of the First International Transradial Practice Survey

OBJECTIVES The aim of this study was to evaluate practice of transradial approach (TRA). BACKGROUND TRA has been adopted as an alternative access site for coronary procedures. METHODS A questionnaire was distributed worldwide with Internet-based software. RESULTS The survey was conducted from August 2009 to January 2010 among 1,107 interventional cardiologists in 75 countries. Although pre-TRA dual hand circulation testing is not uniform in the world, >85% in the U.S. perform Allen or oximetry testing. Right radial artery is used in almost 90%. Judkins catheters are the most popular for left coronary artery angiographies (66.5%) and right coronary artery angiographies (58.8%). For percutaneous coronary intervention (PCI), 6-F is now standard. For PCI of left coronary artery, operators use standard extra back-up guiding catheters in >65% and, for right coronary artery 70.4% use right Judkins catheters. Although heparin remains the routine antithrombotic agent in the world, bivalirudin is frequently used in the U.S. for PCI. The incidence of radial artery occlusion before hospital discharge is not assessed in >50%. Overall, approximately 50% responded that their TRA practice will increase in the future (68.4% in the U.S.). CONCLUSIONS TRA is already widely used across the world. Diagnostic and guiding-catheters used for TRA remain similar to those used for traditional femoral approach, suggesting that specialized radial catheters are not frequently used. However, there is substantial variation in practice as it relates to specific aspects of TRA, suggesting that more data are needed to determine the optimal strategy to facilitate TRA and optimize radial artery patency after catheterization.

End-systolic volume as a predictor of postoperative left ventricular performance in volume overload from valvular regurgitation.

Abstract Although over-all cardiac performance may remain normal in patients with left ventricular volume overload from valvular regurgitation, impairment of myocardial function may occur and remain undetected by currently accepted methods of assessing ventricular performance. Since end-systolic volume reflects myocardial contractile function yet is independent of preload, we assessed preoperative end-systolic volume as a measure of myocardial function in 41 patients with aortic regurgitation, mitral regurgitation or both. Preoperative end-systolic volume was compared to postoperative left ventricular performance as measured by postoperative echocardiographic per cent dimension change (% ΔD) and New York Heart Association class. Preoperative end-systolic volume correlated well with postoperative left ventricular performance in patients with aortic regurgitation (r = 0.77) or mitral regurgitation (r = 0.73). Much poorer correlations existed for preoperative ejection fraction, enddiastolic volume or left ventricular end-diastolic pressure. Preoperative end-systolic volume also predicted patients at high risk for perioperative cardiac death, with all such cardiac deaths occurring in patients with an end-systolic volume >60 cc/m 2 . Again, both preoperative ejection fraction and end-diastolic volume were less precise predictors of surgical outcome. Patients with aortic regurgitation appeared to tolerate a larger end-systolic volume better than those with mitral regurgitation. End-systolic volume is an easily determinable parameter of left ventricular function which is independent of the abnormal preload that occurs in mitral regurgitation and aortic regurgitation and appears to provide a measure for the onset of myocardial dysfunction in patients with these lesions. Whether this myocardial dysfunction is due to a depressed inotropic state of individual sarcomeres, a stress-shortening imbalance or to other factors is unknown, but its presence has major prognostic importance.

Refractory ergonovine induced coronary vasospasm: importance of intracoronary nitroglycerin

Recent experience has suggested that the ergonovine maleate test is a safe procedure for the diagnosis of variant angina pectoris, because ergonovine-induced coronary vasospasm has generally been reversible by sublingual nitroglycerin. This report describes five cases of ergonovine-induced coronary vasospasm that were refractory to sublingual nitroglycerin. Four of these patients had cardiac arrest. In two patients the vasospasm was responsive to intracoronary nitroglycerin administration. Three patients died as a reuslt of the test. The two survivors differed from the nonsurvivors in the total dose or ergonovine given (0.1 and 0.15 mg versus 0.17, 0.3 and 0.3 mg, respectively) and in the method of administration of ergonovine. The survivors were given serial doses of 0.05 mg each whereas the three nonsurvivors received either larger initial doses (0.1 followed by 0.07 mg) or progressive incremental doses (0.05, 0.1 and 0.15 mg serially). Sublingual nitroglycerin, given to all five patients, and intravenous nitroglycerin, given to three of the five, were ineffective in reversing vasospasm. Intracoronary nitroglycerin favorably altered the course of the survivors. Thus, the ergonovine maleate test is not benign and may cause severe coronary vasospasm that is unresponsive to sublingual and intravenous nitroglycerin, but may be reversed by intracoronary nitroglycerin.

Estimation of left ventricular volumes in man from biplane cineangiograms filmed in oblique projections

Abstract In patients with coronary artery disease, right and left anterior oblique views of the left ventricle are considered optimal for assessment of regional wall motion, but the accuracy of ventricular volumes determined from these projections has not been validated. Eleven postmortem left ventricular casts were filmed with the 35 mm cine technique in the 30 ° right anterior oblique and 60 ° left anterior oblique positions, and volumes were calculated using the area-length method. True volume, assessed from volume displacement, ranged from 15 to 185 cc. Calculated volume (V oblique ) slightly but consistently overestimated true volume (V T ), with close correlation and a small standard error of the estimate (SEE):V T = 0.989 V oblique − 8.1 cc, r = 0.99, SEE = 8 cc. With use of this regression equation, values for left ventricular volumes and ejection fraction were calculated from biplane oblique (30 ° right anterior oblique/60 ° left anterior oblique) cineanglograms In 17 normal adults. Values for end-diastolic volume index (72 ± 15 cc/m 2 [mean ± standard deviation]), end-systolic volume index (20 ± 8 cc/m 2 ), stroke volume Index (51 ± 10 cc/m 2 ) and ejection fraction (0.72 ± 0.08) were similar to those reported by others. Examination of the effects of variable obliquity suggests that strict standardization of the degree of obliquity is necessary to offset variation In the long axis in the left anterior oblique projection caused by foreshortening.

Factors contributing to altered left ventricular diastolic properties during angina pectoris.

Mechanisms involved in the altered left ventricular (LV) diastolic properties during angina were studied in 26 patients with coronary artery disease. Angina was induced by rapid atrial pacing and measurements were made at rest and during angina in the immediate post-pacing period. No changes occurred in heart rate (71 ± 3 to 73 ± 3 beats/min, NS) or right ventricular (RV) end-diastolic pressure (10 ± I to 11 ± 1 mm Hg, NS), while significant increases occurred in LV end-diastolic pressure (17 i 1 to 30 ± 1 mm Hg, p lt; 0.01), aortic diastolic pressure (74 ± 3 to 80 ± 3 mm Hg, p lt; 0.01), coronary sinus blood flow (133 ± 15 to 212 ± 32 ml/min, p lt; 0.01), and the time constant (T) of LV pressure fall in early diastole (43 ± 2 to 58 ± 4 msec, p lt; 0.01). Despite the rise in arterial pressure, a significant fall was observed in peak negative dP/dt (1961 ± 106 to 1751 ± 80 mm Hg/sec, p lt; 0.01). Changes in RV end-diastolic pressure do not explain the increased LV end-diastolic pressure during angina. Increased aortic pressure and coronary blood flow may contribute, but the simultaneous fall in peak negative dP/dt and rise in T suggest that impaired ventricular relaxation is an important factor contributing to the previously demonstrated alteration in LV diastolic properties during angina pectoris.

Effect of angina on the left ventricular diastolic pressure-volume relationship.

The increased left ventricular end-diastolic pressure associated with myocardial ischemia was studied in 19 patients at cardiac catheterization. Single plane left ventriculograms were performed using high fidelity micromanometer tipped catheters before and immediately following rapid atrial pacing. Left ventricular diastolic properties were evaluated by constructing diastolic pressure-volume curves from the simultaneous pressure and volume data. In seven control patients, there was no significant change in left ventricular hemodynamics or the diastolic pressure-volume curve after atrial pacing. Twelve patients with significant coronary artery disease developed angina during pacing and had an increased left ventricular end-diastolic pressure (18 ± 2 mm Hg, control, vs 30 ± 2 mm Hg, angina, P < X01) in the immediate post-pacing period. In these patients, the post-pacing ejection fraction was modestly decreased (0.63 ± 0.03, control, vs 0.57 ± 0.03, angina P < 0.01), and left ventricular volumes at end systole (59 ± 8 cc, control, vs 74 ± 9 cc, angina, P < 0.01) and end diastole (158 ± 10 cc, control, vs 170 ± 11 cc, angina, P < 0.0125) were increased. The post-pacing diastolic pressure-volume curves in all 12 patients were shifted upward as compared with control so that for any given diastolic volume, pressure was higher during angina. The data indicate that the increased left ventricular diastolic pressure during myocardial ischemia is the result of both impaired left ventricular systolic performance and altered left ventricular diastolic properties.

Comparison of metabolic and vasoconstrictor stimuli on coronary vascular resistance in man.

Coronary blood flow (CBF) is considered proportional to metabolic demand (MVO,). However, recent studies have reported inappropriate vasoconstrictor response to a-adrenergic stimulation in patients with coronary artery disease (CAD). To assess the interaction of vasodilatory reserve and adrenergic vasoconstriction, we compared changes in coronary vascular resistance (CVR) during the metabolic stress of rapid atrial pacing and during the a-adrenergic stimulus of cutaneous cold (cold pressor test, CPT) in 13 control patients and 14 patients with CAD. Similar heart rates were achieved with pacing in both control and CAD patients, and both groups had a similar hypertensive response to CPT; thus, both pacing and CPT increased major determinants of MVO2. In association with this increased MVO, CVR decreased with rapid pacing in control and CAD patients (-24% and -27%, respectively), but increased in CAD patients (+24%) during CPT. Seven of 13 CAD patients actually had a reduction in CBF, whereas CBF increased in all control patients in response to CPT. Compression of intramural coronary vessels by elevated left ventricular diastolic pressure was excluded as a pathogenic mechanism for increase in CVR in two CAD patients who showed marked reduction in CBF during CPT.These data are further evidence that patients with CAD may have limited coronary vasodilatory mechanisms. Superimposed a-adrenergically mediated coronary vasoconstriction may contribute significantly to myocardial ischemia in patients with CAD.

Long-term safety and efficacy with paclitaxel-eluting stents: 5-year final results of the TAXUS IV clinical trial (TAXUS IV-SR: Treatment of De Novo Coronary Disease Using a Single Paclitaxel-Eluting Stent).

OBJECTIVES The pivotal TAXUS IV (TAXUS IV-SR: Treatment of De Novo Coronary Disease Using a Single Paclitaxel-Eluting Stent) trial evaluated the long-term safety and effectiveness of the paclitaxel-eluting stent (PES) compared with an otherwise identical bare-metal stent (BMS) in a relatively uncomplicated population of patients with a single de novo lesion in a native coronary vessel, treated between March and July 2002. BACKGROUND Long-term follow-up is required to determine whether the early safety and efficacy of drug-eluting stents are maintained. METHODS The primary end point of this prospective, randomized, double-blind trial was 9-month ischemia-driven target vessel revascularization (TVR) for PES versus the BMS control. Follow-up was complete in 1,230 (95.1%) of 1,294 randomized evaluable patients at 5 years. RESULTS Compared with BMS, PES significantly reduced TVR at 9 months (12.1% vs. 4.7%; p < 0.0001); this benefit was maintained through 5 years (27.4% vs. 16.9%; p < 0.0001), given comparable TVR rates for BMS and PES between years 1 and 5 (4.1%/year vs. 3.3%/year; respectively, p = 0.16). Similar patterns were observed for composite major adverse cardiac events (MACE) (32.8% BMS vs. 24.0% PES, p = 0.0001 at 5 years). Stent thrombosis was comparable for PES and BMS at 9 months (0.8% BMS vs. 0.8% PES; p = 0.98) and at 5 years (2.1% BMS vs. 2.2% PES, p = 0.87). The overall revascularization benefits of PES were consistent across multiple subgroups, including sex, diabetes, left anterior descending artery lesion location, reference vessel diameter, lesion length, and multiple stents. CONCLUSIONS These 5-year results demonstrate the long-term safety and sustained efficacy of PES compared with BMS in patients with noncomplex lesions. (TAXUS IV-SR: Treatment of De Novo Coronary Disease Using a Single Paclitaxel-Eluting Stent; NCT00292474).

Effects of Sodium Nitroprusside on Left Ventricular Diastolic Pressure-Volume Relations

The effect of sodium nitroprusside on the relationship between left ventricular pressure and volume during diastole was studied in 11 patients with congestive heart failure. Nitroprusside was infused to lower mean arterial pressure approximately 20-30 mm Hg. High fidelity left ventricular pressures were recorded in all patients simultaneously with left ventricular cineangiography (biplane in eight and single plane in three patients), allowing precise measurement of pressure and volume throughout the cardiac cycle. Left ventricular diastolic pressure-volume curves were constructed in each patient from data obtained before and during nitroprusside infusion. In 9 of 11 patients there was a substantial downward displacement of the diastolic pressure-volume curve during nitroprusside infusion, with left ventricular pressure being lower for any given volume with nitroprusside. Serial left ventricular cineangiograms performed 15 min apart in six additional subjects who did not receive sodium nitroprusside showed no shift in the diastolic pressure-volume relation, indicating that the shift seen with nitroprusside was not due to the angiographic procedure itself. A possible explanation for the altered diastolic pressure-volume relationships with nitroprusside might be a direct relaxant effect of nitroprusside on ventricular muscle, similar to its known relaxant effect on vascular smooth muscle. Alternatively, nitroprusside may affect the diastolic pressure-volume curve by affecting viscous properties or by altering one or more of the extrinsic constraints acting upon the left ventricle.