Dinesh Arab

Invasive assessment of mitral regurgitation: Comparison of hemodynamic parameters

Objectives: We sought to analyze several new hemodynamic characteristics which address the interplay of left atrial (LA) and left ventricular (LV) pressures, as well as to re‐analyze several other V wave characteristics employed in the determination of mitral regurgitation (MR) severity in order to determine which, if any, had adequate correlation with grade of MR for clinical utility. Background: Invasive assessment of mitral regurgitation includes analysis of intracardiac pressures and LV angiography. The V wave, when obtained from the pulmonary capillary wedge position (PCWP), and its various characteristics are believed to be of limited value for prediction of MR severity. Method: We analyzed the transeptal pressure tracings of patients with various degrees of MR. Several relationships from the simuItaneous pressure‐time curves of the LA and LV were defined. Biplane left ventricular angiography was used to grade MR. Correlation between each parameter and MR grade was determined by calculating a Pearson correlation coefficient. Results: The ratio of the area under the V wave to the LV systolic area (Va/LVa) best correlates with the degree of MR with a Pearson correlation coefficient of 0.60. The Va/LVa was significantly lower in patients with 0−1+ MR compared to ≥2+ MR (0.14 vs. 0.23 p = 0.002). Conclusions: Invasive hemodynamic assessment of MR severity could be enhanced by calculating our new ratio, Va/LVa, due to its ability to account for LV work that is lost to the LA with a proportional decrease in forward or useful LV work with progressively increasing severity of MR.

Alcohol septal ablation after failed surgical myectomy.

We describe the case of a successful alcohol septal ablation in a patient with persistent gradient and severe symptoms postsurgical myectomy. The alcohol ablation of the thickened septum abolished the left ventricular outflow gradient and the systolic anterior motion (SAM) of the mitral valve. Although the surgical literature advocates for mitral valve replacement in patients who continue to have SAM with significant outflow obstruction postmyectomy, targeted alcohol septal ablation of the remaining septum appears to be an attractive alternative.

Presence of asymmetric dimethylarginine gradients across high-grade lesions in patients with coronary artery disease.

BackgroundAsymmetric dimethylarginine, an endogenous inhibitor of nitric oxide synthase, is a systemic marker of endothelial dysfunction. Although experimental evidence indicates that asymmetric dimethylarginine may play an important role in atherogenesis, local asymmetric dimethylarginine levels have not been measured in vivo. ObjectivesWe sought to determine whether: (i) asymmetric dimethylarginine is elevated locally at sites of coronary lesions, (ii) systemic asymmetric dimethylarginine concentrations correlate with local levels, and (iii) percutaneous coronary intervention produces immediate local asymmetric dimethylarginine elevation. MethodsIn patients undergoing percutaneous coronary intervention (n=15), blood samples were obtained from a peripheral venous site, the coronary ostium proximal to the lesion and the coronary vessel distal to the lesion, before percutaneous coronary intervention. Samples were also obtained distal to the coronary lesion immediately after percutaneous coronary intervention and from the peripheral venous line 24 h after percutaneous coronary intervention. ResultsAsymmetric dimethylarginine gradients were present across the coronary bed: local asymmetric dimethylarginine (μmol/l) was significantly higher distal to coronary lesions compared with proximally (2.39±1.27 vs. 1.52±0.68, P=0.005), and to systemic venous levels (2.39±1.27 vs. 1.17±0.72, P=0.001). Local asymmetric dimethylarginine did not increase immediately after percutaneous coronary intervention (1.88±0.89 vs. 2.39±1.27, P=0.11). Peripheral venous percutaneous coronary intervention levels 24 h after percutaneous coronary intervention were similar to baseline values (1.17±1.2 vs. 1.17±0.72, P=0.98). ConclusionAsymmetric dimethylarginine gradients exist across coronary lesions, suggesting asymmetric dimethylarginine release at the plaque site. Local asymmetric dimethylarginine accumulation may contribute to the endothelial dysfunction associated with high-grade coronary lesions. Peripheral asymmetric dimethylarginine is a marker of generalized endothelial dysfunction, but our findings highlight its limitation in detecting focal injury.