No abstract

The clinical use of cryopreserved allograft valves is rapidly increasing. Viability of valve leaflet fibroblasts has been proposed to be critical to durability. Harvesting of allograft valves involves variable warm ischemia times, defined as the time from cessation of donor heart beat to initial cooling for transport. This ischemic period has been implicated as one of the more critical periods of injury to leaflet cell, even though adequate characterization of this potentially injurious phase has never been accomplished. The present study was undertaken to characterize the metabolic response to warm ischemia in a porcine valve leaflet model. Valve handling was similar to clinical valve harvest and transport protocols. Injury was assessed by protein (1H) and phosphorus (31P) magnetic resonance spectroscopy of 224 porcine semilunar valves. Leaflets were analyzed over time for lactate accumulation and ATP degradation. A radiolabelled incubation assay (48 valves) was used to measure proline accumulation by fibroblasts. Electron microscopy was performed on 36 valves with varying warm ischemia times. ATP stores were entirely depleted after 2 h hypoxia (p less than 0.05). However, lactate continued to accumulate over 24 h. Although aerobic metabolism ceased after 2 h warm ischemia, anaerobic metabolism continued for up to 24 h, which may represent an extended window for harvesting fresh tissue for allograft valve implantation.

No abstract

Introduction/Objective High take-off coronary arteries (HTO) are defined by coronary ostia arising above the sinotubular junction (STJ). Although asymptomatic in most individuals, there is increasing evidence that HTO is a risk factor for sudden cardiac death. Here we present two patients where HTO contributed to death. Methods/Case Report Patient A was a 52 year old morbidly obese male with atypical chest pain, new inferior ST elevations and troponinemia. Multiple coronary angiographies did not reveal any stenosis, but 3 stents were placed in the RCA due to concern for vasospasm. 3 days later the patient died. Autopsy revealed cardiac tamponade and non- atherosclerotic ischemic heart disease with remote apical LV scar and diffuse patchy interstitial fibrosis in the myocardium, which could be attributed to HTO of the RCA 0.5 cm above the STJ and early intramuscular courses of both coronaries. Multiple angiographies likely caused iatrogenic coronary injury and subsequent tamponade. Patient B was a healthy 33 year old female at 34 weeks gestation, who developed anaphylaxis during IV iron infusion for severe iron deficiency anemia. She was transferred to the OR for emergent C-section. Minutes after delivery she died. Autopsy revealed HTO, with coronary ostia being 0.4 cm and 0.7 cm above the STJ, respectively and acute angle take-off of LCA. No atherosclerosis was noted. The inability to increase myocardial perfusion through the coronary arteries during a high stress situation due to pregnancy, iron deficiency anemia and anaphylaxis likely contributed to lethal myocardial ischemia. Results (if a Case Study enter NA) NA Conclusion HTO and other coronary artery anomalies (CAAs) should be considered in cases of cryptogenic acute and chronic myocardial ischemia. Hemodynamic characterization of HTO, including those < 1 cm above the STJ in presence and absence of other CAAs may help better understand their pathophysiologic significance. Antemortem diagnosis requires high clinical suspicion and appropriate surgical intervention could be life-saving.

No abstract