Effects of angiotensin-converting enzyme inhibition on left ventricular geometric patterns in patients with essential hypertension

Quinaprilat: a review of its pharmacokinetics, pharmacodynamics, toxicological data and clinical application

BACKGROUND

Quinaprilat is an ACE inhibitor for intravenous use especially in patients with arterial hypertension or chronic heart failure. In contrast to the oral prodrug quinapril, it has not been approved for clinical application.

OBJECTIVE

In this review, the pharmacokinetic and pharmacodynamic profile of quinaprilat as well as toxicological data and results of preclinical and clinical studies are summarized.

METHODS

In a PubMed search for the terms "quinaprilat" and "quinapril", literature relevant for this review was selected.

RESULTS

Quinaprilat is a potent nonsulfhydryl selective ACE inhibitor with a short elimination half-life of 2 - 3 h, but due to slow dissociation from tissue ACE, once daily dosing is sufficient for effective ACE inhibition. Quinaprilat is excreted mainly in urine. In long-term animal studies, quinaprilat was not teratogenic, mutagenic or carcinogenic. However, due to the risk of fetal and neonatal morbidity and death, it should not be administrated in pregnancy. Quinaprilat is characterized by an excellent safety profile; adverse events occur infrequently and are rarely serious.

CONCLUSION

Quinaprilat is an attractive ACE inhibitor, which potently inhibits tissue ACE.

Cardiac response to pressure overload in 129S1/SvImJ and C57BL/6J mice: temporal- and background-dependent development of concentric left ventricular hypertrophy

Left ventricular hypertrophy (LVH), a risk factor for cardiovascular morbidity and mortality, is commonly caused by essential hypertension. Three geometric patterns of LVH can be induced by hypertension: concentric remodeling, concentric hypertrophy, and eccentric hypertrophy. Clinical studies suggest that different underlying etiologies, genetic modifiers, and risk of mortality are associated with LVH geometric patterns. Since pressure overload-induced LVH can be modeled experimentally using transverse aortic constriction (TAC) and since C57BL/6J (B6) and 129S1/SvImJ (129S1) strains, which have different baseline cardiovascular phenotypes, are commonly used, we conducted serial echocardiographic studies to assess cardiac function up to 8 wk of post-TAC in male B6, 129S1, and B6129F1 (F1) mice. B6 mice had an earlier onset and more pronounced impairment in contractile function, with corresponding left and right ventricular dilatation, fibrosis, change in expression of hypertrophy marker, and increased liver weights at 5 wk of post-TAC. These observations suggest that B6 mice had eccentric hypertrophy with systolic dysfunction and right-sided heart failure. In contrast, we found that 129S1 and F1 mice delayed transition to decompensated heart failure, with 129S1 mice exhibiting preserved systolic function until 8 wk of post-TAC and relatively mild alterations in histology and markers of hypertrophy at 5 wk post-TAC. Consistent with concentric hypertrophy, our results show that these strains manifest different cardiac responses to pressure overload in a time-dependent manner and that genetic susceptibility to initial concentric hypertrophy is dominant to eccentric hypertrophy. These results also imply that genetic background differences can complicate interpretation of TAC studies when using mixed genetic backgrounds.

Left ventricular mass and geometry and the risk of ischemic stroke

BACKGROUND AND PURPOSE

Left ventricular hypertrophy (LVH) is a risk factor for cardiovascular events, but its effect on ischemic stroke risk is established mainly in whites. The effect of LV geometry on stroke risk has not been defined. The aim of the present study was to evaluate whether LVH and LV geometry are independently associated with increased ischemic stroke risk in a multiethnic population.

METHODS

A population-based case-control study was conducted on 394 patients with first ischemic stroke and 413 age-, sex-, and race-ethnicity-matched community control subjects. LV mass was measured by transthoracic echocardiography. LV geometric patterns (normal, concentric remodeling, concentric or eccentric hypertrophy) were identified. Stroke risk associated with LVH and different LV geometric patterns was assessed by conditional logistic regression analysis in the overall group and age, sex, and race-ethnic strata, with adjustment for established stroke risk factors.

RESULTS

Concentric hypertrophy carried the greatest stroke risk (adjusted odds ratio [OR], 3.5; 95% confidence interval [CI], 2.0 to 6.2), followed by eccentric hypertrophy (adjusted OR, 2.4; 95% CI, 2.0 to 4.3). Concentric remodeling carried slightly increased stroke risk (adjusted OR, 1.7; 95% CI, 1.0 to 2.9). Increased LV relative wall thickness was independently associated with stroke after adjustment for LV mass (OR, 1.6; 95% CI, 1.1 to 2.3).

CONCLUSIONS

LVH and abnormal LV geometry are independently associated with increased stroke risk. LVH is strongly associated with ischemic stroke in all age, sex, and race-ethnic subgroups. Increased LV relative wall thickness imparts an increased stroke risk after adjustment for LV mass and is of additional value in stroke risk prediction.

Left ventricular remodeling impairs coronary flow reserve in hypertensive patients

BACKGROUND

In arterial hypertension, changes in both left ventricular mass and geometry may occur. Concentric left ventricular remodeling (i.e. an increased wall thickness relative to end diastolic diameter) has been implicated as an independent cardiovascular risk factor in hypertensive patients. The influence of concentric remodeling on the coronary microcirculation is not known.

OBJECTIVE

To investigate the impact of left ventricular geometry on coronary flow reserve in patients with arterial hypertension and angiographically normal coronary arteries.

METHODS

Following exclusion of coronary artery disease by cardiac catheterization, coronary flow reserve (dipyridamole, 0.5 mg/kg body weight intravenously; argon gas-chromatographic method) was measured in 49 patients with arterial hypertension and in six age-matched controls. Hypertensive patients were grouped by echocardiographic findings according to left ventricular mass and relative left ventricular wall thickness (i.e. left ventricular posterior wall plus septal thickness divided by end diastolic diameter): seven patients had normal left ventricular mass and geometry, 19 had eccentric hypertrophy (i.e. normal relative wall thickness but increased mass), concentric remodeling (i.e. normal mass but increased relative wall thickness) was present in nine patients, and 14 patients had concentric hypertrophy.

RESULTS

There was a marked reduction in coronary flow reserve in all hypertensive groups as compared with control values (4.2 +/- 0.5). Within the hypertensive subgroups, the coronary flow reserve was differentially reduced in the following rank order: concentric remodeling (2.0 +/- 0.7) approximately concentric hypertrophy (2.3 +/- 0.8) < eccentric hypertrophy (2.9 +/- 0.6) mu normal geometry (2.7 +/- 0.4). Multi-factorial regression analysis showed that the relative wall thickness but not left ventricular mass was independently linked to the coronary flow reserve.

CONCLUSIONS

Concentric left ventricular remodeling is an independent predictor of the coronary flow reserve in hypertensive patients with chest pain and normal coronary angiogram. The impairment of the coronary microcirculation may contribute to the excess cardiovascular event rate associated with hypertensive concentric left ventricular remodeling.