Conduit choice for coronary artery bypass grafting after mediastinal radiation

ObjectivePatients who have undergone prior mediastinal radiation might require coronary artery bypass grafting. However, there is some concern regarding potential radiation damage to the internal thoracic artery. Our objective was to assess the late patency of the internal thoracic artery and venous grafts in patients with prior mediastinal radiation.MethodsPatients undergoing coronary artery bypass grafting at our clinic after prior mediastinal radiation were identified, and medical records, including operative reports, clinical notes, and coronary angiography, were reviewed.ResultsBetween 1985 and 2005, 138 patients had coronary artery bypass grafting after mediastinal radiation. Of these, 25 underwent clinically indicated postoperative angiography. The mean patient age was 56.1 ± 13.8 years, and 24% were female. All patients received between 3000 and 6000 rads in fractionated doses. Seventy-two percent of patients had 3-vessel coronary artery disease. At late angiography (mean, 2.2 years), 6 (32%) of 19 internal thoracic arteries and 13 (27%) of 48 venous or radial arterial conduits showed stenosis of 70% or greater (P = .72). Assessing only grafts that were anastomosed to the left anterior descending coronary artery, 35% (6 of 17) of internal thoracic artery grafts and 60% (3 of 5) of non–internal thoracic artery grafts showed narrowing of 70% or greater (P = .61). Among patients who received a graft to the left anterior descending coronary artery (n = 113), however, age-adjusted survival at 5 years was superior among those receiving an internal thoracic artery graft to the left anterior descending coronary artery.ConclusionsInternal thoracic artery graft patency among patients with prior radiation was less than expected and similar to that for venous grafts, although the effect of conduit disease versus distal target vessel runoff is unknown. Despite this, late survival was superior among those receiving an internal thoracic artery graft to the left anterior descending coronary artery. These data support use of an internal thoracic artery graft to the left anterior descending coronary artery when it appears grossly to be an acceptable conduit

When should a mechanical tricuspid valve replacement be considered?

BackgroundIsolated mechanical tricuspid valve replacement (mTVR) is uncommon, early mortality is reported to be high, and little is known regarding the long-term outcome. We sought to evaluate the long-term outcome of mTVR.MethodsFrom 1980 to 2007, isolated mTVR was performed in 64 patients (33 men) at our institution; the median age was 45.5 years (6-71 years). There were 2192 tricuspid valve (TV) repairs and 137 isolated bioprosthetic TV replacements during the same time interval. Valve dysfunction was caused by congenital TV abnormality in 45 patients (70%), carcinoid heart disease in 13 (20%), traumatic TV regurgitation in 3 (5%), and other reason in 3 (5%). Twenty-three patients (36%) had at least 1 previous cardiac procedure (TV repair in 8 and bioprosthetic TV replacement in 7).ResultsMechanical prostheses used included Starr-Edwards (before 1993) in 36 patients (56%) and bileaflet prostheses in 28 (44%). Concomitant procedures included atrial septal defect closure in 28 (44%), arrhythmia surgery in 11 (17%), and pulmonary valvectomy for carcinoid disease in 10 patients (16%). Early mortality occurred in 5 patients (7.8%). Early morbidity included a permanent pacemaker in 9 (14%) and reexploration for bleeding in 2 patients (3%). Mean follow-up was 6 years (maximum 22.4 years). Five- and 10-year survival was 65% and 58%, respectively. There was no valve-related mortality. Late morbidity included valve thrombosis in 5 patients (8%); 3 were managed nonoperatively and 2 underwent TV rereplacement.ConclusionsIsolated mTVR still leads to increased early mortality. A mechanical valve can be considered in select situations when anticoagulation is necessary and in the presence of good right ventricular function

Does the dilated ascending aorta in an adult with congenital heart disease require intervention?

ObjectivesThere is increasing attention to prophylactic replacement of the moderately dilated ascending aorta at aortic valve surgery. Moderate ascending aortic dilatation is common in adult patients with conotruncal anomalies. There are no data outlining actual risk of progressive ascending aortic dilatation or dissection to provide management guidelines.MethodsFrom December 1973 through January 2008, 81 consecutive adults (median age, 34 years; range, 18--59 years) with conotruncal anomalies underwent operation on the aortic root, ascending aorta, or aortic valve. Primary cardiac diagnoses included tetralogy of Fallot with or without pulmonary atresia in 60 patients, truncus arteriosus in 12, double-outlet right ventricle in 6, and other in 3. Indications for operation included aortic regurgitation in 69 patients, supracoronary ascending aneurysm in 16, aortic stenosis in 5, and other in 8. Median ascending aortic size was 45 mm (23--80 mm).ResultsOperations included isolated aortic valve repair/replacement in 63 patients, combined aortic valve replacement and reduction aortoplasty in 9, aortic root replacement in 7, and isolated ascending aortic replacement in 2. Four patients required reoperation during a median follow-up of 3.8 years (maximum 31 years). There were no ascending aortic reoperations after previous reduction aortoplasties or supracoronary ascending aortic grafts, and there were no late aortic dissections.ConclusionsModerate ascending aortic enlargement is common among patients with conotruncal anomalies coming to operation, but aortic dissection is rare, as is subsequent need for aortic reoperation. Despite current enthusiasm for prophylactic operations on the ascending aorta in patients with acquired disease, these data suggest that the moderately dilated aorta in this setting may be observed

Importance of implant technique on risk of major paravalvular leak (PVL) after St. Jude mechanical heart valve replacement: a report from the Artificial Valve Endocarditis Reduction Trial (AVERT)

Objective: To examine risk factors for major paravalvular leak (PVL) events after mechanical heart valve replacement. Methods: We analyzed outcome of 807 patients randomized into the Artificial Valve Endocarditis Reduction Trial (AVERT). The mean follow-up time was 30.6 months and 21 major PVL events were reported. Three additional major PVL events associated with endocarditis were excluded from analysis. All baseline medical history variables, as well as operative parameters (including use of pledgets and suture technique) were examined using Cox regression. Results: Major PVL was reported after 11 aortic, 9 mitral, and 1 double valve replacement. 6/404 (1.5%) patients with conventional valves experienced a major PVL event versus 15/403 (3.7%) in the Silzone group. 10/172 (5.8%) patients with valve suture technique without pledgets experienced a major PVL event versus 11/635 (1.7%) patients with pledgets. Final multivariable model showed that only suture technique without pledgets (p = 0.005) was an independent significant risk factor for major PVL events. Silzone cuff showed a strong trend (p = 0.055). Conclusions: Suture technique without pledgets is an independent significant risk factor for major PVL events. In this study, use of pledgets during valve replacement had a protective effect against subsequent paravalvular leak, supporting the use of buttress reinforcement for valve suture. The use of Silzone cuff, although not statistically significant, showed a strong trend as a risk facto

Effect of the effluent released from the canine internal mammary artery after intraluminal and extraluminal perfusion of acetylcholine and adenosine diphosphate

Segments of the canine internal mammary artery (35 mm in length) were suspended in vitro in an organ chamber containing physiological salt solution (95% O2/5% CO2, pH = 7.4, 37°C). Segments were individually cannulated and perfused at 5 ml/minute using a roller pump. Vasorelaxant activity of the effluent from the perfused internal mammary arteries was bioassayed by measuring the decrease in tension induced by the effluent of the coronary artery endothelium-free ring which had been contracted with prostaglandin F2α (2 × 10-6 M). Intraluminal perfusion of adenosine diphosphate (10-5 M) induced significant increase in relaxant activity in the effluent from the perfused blood vessel. However, when adenosine diphosphate (10-5 M) was added extraluminally to the internal mammary artery, no change in relaxant activity in the effluent was noted. In contrast, acetylcholine produced significant increase in the relaxant activity on the effluent of the perfused internal mammary artery with both intraluminal and extraluminal perfusion. The intraluminal and extraluminal release of endothelium-derived relaxing factor (EDRF) by acetylcholine (10-5 M) can be inhibited by site-specific administration of atropine (10-5 M). These experiments indicate that certain agonists can induce the release of EDRF only by binding to intravascular receptors while other agonists can induce endothelium-dependent vasodilatation by acting on neural side receptors

High-frequency ultrasonic waves cause endothelial dysfunction on canine epicardial coronary arteries

OBJETIVO: Aplicação de energia por ultra-som pode facilitar a remoção da placa ateromatosa, mas o efeito desse procedimento em vasos próximos ainda é matéria de estudos experimentais. MÉTODOS: Para determinar se a energia ultra-sônica compromete a produção de óxido nítrico, segmentos de artérias coronárias caninas foram expostos a baixos (0-10 W) e altos (25 W) níveis de energia por 15 segundos, utilizando-se protótipo de aparelho para a realização de endarterectomia. Após exposição, segmentos das artérias coronarianas foram estudados em organ chambers. Para os ensaios farmacológicos foram utilizadas as seguintes drogas:difosfato de adenosina (ADP), acetilcolina (Ach) e fluoreto de sódio (NaF) para a avaliação do relaxamento dependente do endotélio. O nitroprussiato de sódio (NPS) e o isoproterenol foram utilizados para a avaliação do relaxamento independente do endotélio. RESULTADOS: A aplicação de alta energia ultra-sônica comprometeu o relaxamento dependente do endotélio induzido por ADP (10-9 - 10-4 M), Ach (10-9 - 10-4 M) e NaF (0,5 -9,5 mM) em artérias coronarianas epicárdicas. Entretanto, baixos valores de energia ultra-sônica não alteraram o relaxamento dependente do endotélio (nem o relaxamento máximo e nem a EC50) induzido pelos mesmos agonistas. O relaxamento da musculatura lisa vascular induzido por isoproterenol (10-9 - 10-5 M) ou NPS (10-9 - 10-6 M) não foi comprometido, tanto por baixos, quanto por altos níveis de energia ultra-sônica. CONCLUSÃO: Os experimentos demonstram que altas energias ultra-sônicas alteram a função endotelial. Entretanto, o ultra-som não altera a habilidade de relaxamento da musculatura lisa vascular de artérias caninas epicárdicas.OBJECTIVE: Application of ultrasound energy by an endarterectomy probe can facilitate the removal of atheromatous plaque, but the effect of this procedure on surrounding vessel structure and function is still a matter of experimental investigations. METHODS: To determine whether ultrasound energy impairs the production of nitric oxide or damages vascular smooth muscle function, isolated canine epicardial coronary artery segments were exposed to either high (25 W) or low (0-10 W) ultrasonic energy outputs, for 15 seconds, using an endarterectomy device prototype. After exposure, segments of epicardial coronary artery were studied in organ chambers. The following drugs were used: adenosine diphosphate (ADP), acetylcholine (Ach) and sodium fluoride (NaF) to study endothelium-dependent relaxation and sodium nitroprusside (SNP) and isoproterenol to evaluate endothelium-independent relaxation. RESULTS: Application of high ultrasonic energy power impaired endothelium-dependent relaxation to ADP (10-9 - 10-4 M), Ach (10-9 - 10-4 M) and NaF (0.5 - 9.5 mM) in epicardial coronary arteries. However, low ultrasound energy output at the tip of the probe did not alter the endothelium-dependent relaxation (either maximal relaxation or EC50) to the same agonists. Vascular smooth muscle relaxation to isoproterenol (10-9 - 10-5 M) or SNP (10-9 - 10-6 M) was unaltered following exposure to either low or high ultrasonic energy outputs. CONCLUSION: These experiments currently prove that ultrasonic energy changes endothelial function of epicardial coronary arteries at high power. However, ultrasound does not alter the ability of vascular smooth muscle of canine epicardial coronary arteries to relax.Mayo FoundationCNP