Influences of localized aortic valve damage on coronary artery blood flow in acute aortic regurgitation: an experimental study.

Abstract

We examined the influences of localized aortic valve damage on coronary artery blood flow and the prognosis in acute aortic regurgitation. Aortic regurgitation was produced in 18 open-chest dogs by extensively cutting one of the three aortic cusps with a nerve knife introduced via the cardiac apex. The dogs were separated into three groups of six dogs each. In each group the noncoronary cusp (NCC), the right coronary cusp (RCC), or the left coronary cusp (LCC) was cut. Aortic and left ventricular pressures; the phasic aortic, left anterior descending (LAD), and right coronary artery (RCA) blood flows; and electrocardiograms were simultaneously recorded before and after production of acute AR. All dogs in the NCC and RCC groups survived for at least 30 to 60 min, but all dogs in the LCC group died after 5 to 9 min of production of acute AR due to left ventricular failure. After 2 min of aortic regurgitation, the total, systolic, and diastolic LAD flows were 39 + 14, 19 9, and 20 8 ml/min (mean SD) inthe NCC group, 41 + 15, 31 ± 9, and 10 + 6 ml/min in the RCC group, and 9 + 5, 19 5, and -10 ± 2 ml/min in the LCC group, respectively. The

In Vitro Testing of a Temporary Catheter-Based Aortic “Parachute” Valve

“…These in vitro data support earlier in vivo data, demonstrating that valve removal in a beating heart causes massive regurgitation and drastically reduces cardiac output. 10,11 Therefore, the application of a minimally invasive valve removal device needs to be paired with a means to prevent regurgitation while the native valve is being removed and a stented replacement valve is being placed. To our knowledge, our prototype parachute valve is the first device designed for this purpose and can function as an easy-to-place, temporary aortic valve.…”

Development of a Re‐Positionable Aortic Stent‐Valve: A Preliminary Study in Swine

“…In existing stent‐valves that are expanded directly over native aortic leaflets, coronary artery obstruction by displaced native leaflet or friable valvular debris may result 4,5 . Concerning such characteristics, our stent‐valve should be applied for the treatment of acute aortic insufficiency to maintain coronary artery blood flow 13 . However, our stent‐valve cannot be applied for the treatment of aortic stenosis, as the expansile force of our stent‐valve is insufficient.…”

“…4,5 Concerning such characteristics, our stentvalve should be applied for the treatment of acute aortic insufficiency to maintain coronary artery blood flow. 13 However, our stent-valve cannot be applied for the treatment of aortic stenosis, as the expansile force of our stent-valve is insufficient. When balloon valvuloplasty results in acute aortic insufficiency, our stent-valve may be useful for preventing regurgitant flow through torn native aortic leaflets.…”

Myocardial Ischemia in Severe Aortic Regurgitation Despite Angiographically Normal Coronary Arteries

“…The localization of perfusion defects in our study (mainly involving the anterior segment) supports the prior observations in an animal model. Retrograde coronary flow was demonstrated in a dog model by Nakao et al (1987). Shortly after the onset of aortic regurgitation, left anterior descending artery (LAD) flow decreased significantly (Nakao et al 1987).…”

“…Retrograde coronary flow was demonstrated in a dog model by Nakao et al (1987). Shortly after the onset of aortic regurgitation, left anterior descending artery (LAD) flow decreased significantly (Nakao et al 1987). The anatomical location of the left coronary cusp (anatomically higher than right coronary cusp) might make the left coronary system more prone to flow reversal in the setting of disturbed flow dynamics.…”