Comparison of diastolic septal perforator flow velocities in hypertrophic cardiomyopathy versus hypertensive left ventricular hypertrophy

In this study, we measured diastolic septal perforator flow velocities by Doppler transthoracic echocardiography (TTE) in patients with hypertrophic cardiomyopathy (HCM). Using color-guided pulsed Doppler TTE, septal perforator flow velocity recordings were attempted in 69 patients and successfully recorded in 47 (68%). First, we compared 14 patients with HCM to 12 controls and to 11 patients with hypertension with left ventricular hypertrophy. Next, in 10 additional patients with HCM, we compared the septal velocities with the epicardial left anterior descending artery (LAD) velocities recorded during the same TTE study. In the patients with HCM, the peak septal diastolic velocities were twice that of the normal controls (88 +/- 40 vs 41 +/- 13 cm/s) and also higher than in hypertensive left ventricular hypertrophy (51 +/- 18 cm/s, p < 0.0001). All 10 patients with HCM showed a step-up of peak diastolic velocity from the LAD to the septal perforator from 41 +/- 9 to 72 +/- 17 cm/s (p < 0.0001). Three patients with HCM had surgical septal myectomy. These patients had luminal narrowings of the small intramural arteries at histopathologic examination. In conclusion, pulsed Doppler measurement of septal perforator flow velocities is feasible. In HCM, the epicardial coronary arteries enlarge to accommodate increased flow, and diastolic velocity is normalized. In contrast, the increased velocities in the septal branches of patients with HCM are similar to those previously observed in tunnel-like obstructions. These findings suggest that in HCM, notwithstanding an increase in coronary flow, hemodynamically significant narrowings are present in the septal branches. Doppler TTE may become useful for evaluation of abnormal intramural coronary flow in HCM.

Cardiac power is the strongest hemodynamic correlate of mortality in cardiogenic shock: A report from the SHOCK trial registry

OBJECTIVES

We sought to analyze clinical, angiographic, and outcome correlates of hemodynamic parameters in cardiogenic shock.

BACKGROUND

The significance of right heart catheterization in critically ill patients is controversial, despite the prognostic importance of the derived measurements. Cardiac power is a novel hemodynamic parameter.

METHODS

A total of 541 patients with cardiogenic shock who were enrolled in the SHould we emergently revascularize Occluded Coronaries for cardiogenic shocK (SHOCK) trial registry were included. Cardiac power output (CPO) (W) was calculated as mean arterial pressure x cardiac output/451.

RESULTS

On univariate analysis, CPO, cardiac power index (CPI), cardiac output, cardiac index, stroke volume, left ventricular work, left ventricular work index, stroke work, mean arterial pressure, systolic and diastolic blood pressure (all p < 0.001), coronary perfusion pressure (p = 0.002), ejection fraction (p = 0.013), and pulmonary artery systolic pressure (p = 0.047) were associated with in-hospital mortality. In separate multivariate analyses, CPO (odds ratio per 0.20 W: 0.60 [95% confidence interval, 0.44 to 0.83], p = 0.002; n = 181) and CPI (odds ratio per 0.10 W/m(2): 0.65 [95% confidence interval, 0.48 to 0.87], p = 0.004; n = 178) remained the strongest independent hemodynamic correlates of in-hospital mortality after adjusting for age and history of hypertension. There was an inverse correlation between CPI and age (correlation coefficient: -0.334, p < 0.001). Women had a lower CPI than men (0.29 +/- 0.11 vs. 0.35 +/- 0.15 W/m(2), p = 0.005). After adjusting for age, female gender remained associated with CPI (p = 0.032).

CONCLUSIONS

Cardiac power is the strongest independent hemodynamic correlate of in-hospital mortality in patients with cardiogenic shock. Increasing age and female gender are independently associated with lower cardiac power.

Cardiogenic shock: a summary of the randomized SHOCK trial

Cardiogenic shock is the most common cause of death for patients hospitalized with acute myocardial infarction. The Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock (SHOCK) trial randomly assigned 302 patients with predominant left ventricular failure following an acute myocardial infarction to a strategy of emergency revascularization or initial medical stabilization. Emergency revascularization by either coronary artery bypass grafting or angioplasty was required within 6 hours of randomization. Patients assigned to initial medical stabilization could undergo delayed revascularization at a minimum of 54 hours post-randomization. The primary end point of the study was 30-day all-cause mortality. Overall survival at 30 days did not differ significantly between the emergency revascularization and initial medical stabilization groups (53% vs. 44%; p=0.109). However, at the 6- and 12-month follow-up, there was a significant survival benefit with early revascularization (50% vs. 37%; p=0.027 and 47% vs. 34%; p=0.025, respectively). The benefit appeared to be greatest for those less than 75 years of age, with 20 lives saved at 6 months per 100 patients treated. According to the results of the SHOCK trial, the American College of Cardiology/American Heart Association guidelines for myocardial infarction now recommend emergency revascularization for patients younger than 75 years with cardiogenic shock.