Dearani, Joseph A.

The most common cause of reoperation following repair of atrioventricular septal defect (AVSD) is left atrioventricular valve regurgitation. However, reoperation for subaortic obstruction is required in some, especially after initial repair of partial AVSD. Etiology of reoperation and late outcome were evaluated. Between 1962 and 2007, 146 patients (59 male) underwent reoperation at the authors' institution after prior repair of partial (n = 96) and complete (n = 50) AVSD. Median age at reoperation after repair of partial AVSD was 26 years (range, 10 months to 71 years) and 4.5 years (range, 53 days to 38 years) after repair of complete AVSD. The 3 most common indications for reoperation included left atrioventricular (AV) valve regurgitation in 105 patients, subaortic stenosis in 29, and right AV valve regurgitation in 21. The most common procedures performed included left AV valve repair in 59 (40%) patients, left AV valve replacement in 56 (38%), subaortic fibrous resection/myectomy in 24 (16%), and right AV valve surgery in 19 (13%). Freedom from subsequent reoperation at 10 years was 48% after initial repair of complete AVSD and 84% after initial repair of partial AVSD. During late follow-up, 10-year actuarial survival was 91% and 77% after initial repair of complete and partial AVSD, respectively. The most common indication for reoperation after initial repair of partial or complete AVSD is left AV valve pathology; left ventricular outflow tract obstruction was more common in partial AVSD. Although freedom from subsequent reoperations is higher after initial repair of partial AVSD, these patients have reduced long-term survival when compared with complete AVSD.

Advances in extracorporeal life support have expanded indications for use extending beyond patients undergoing cardiac surgery. The approach to cannulation in patients requiring extracorporeal membrane oxygenation should be individualized and based on the specific clinical scenario in which the need arises. Adherence to proper techniques of vessel visualization, exposure, and cannulation along with accurate placement of cannulae will optimize flows and minimize complications in this setting. Patients in need of mechanical circulatory support require input from a multidisciplinary team approach with systematic clinical evaluation to optimize outcome. If hemodynamics do not initially permit the successful separation from mechanical support, then a systematic search for potentially reversible patient and/ or pump related factors should be undertaken. The success of this therapy is predicated on patient selection, a multidisciplinary team approach in the intensive care unit, adherence to precise technical principles, and repeated patient evaluation.

Background— Mutations in myofilament proteins, most commonly MYBPC3 -encoded myosin-binding protein C and MYH7 -encoded β-myosin heavy chain, can cause hypertrophic cardiomyopathy (HCM). Despite significant advances in structure-function relationships pertaining to the cardiac sarcomere, there is limited knowledge of how a mutation leads to clinical HCM. We, therefore, set out to study expression and localization of myofilament proteins in left ventricular tissue of patients with HCM. Methods and Results— Frozen surgical myectomy specimens from 47 patients with HCM were examined and genotyped for mutations involving 8 myofilament-encoding genes. Myofilament protein levels were quantified by Western blotting with localization graded from immunohistochemical staining of tissue sections. Overall, 25 of 47 (53%) patients had myofilament-HCM, including 12 with MYBPC3-HCM and 9 with MYH7-HCM. As compared with healthy heart tissue, levels of myofilament proteins were increased in patients manifesting a mutation in either gene. Patients with a frameshift mutation predicted to truncate MYBPC3 exhibited marked disturbances in protein localization as compared with missense mutations in either MYBPC3 or MYH7 . Conclusions— In this first expression study in human HCM tissue, increased myofilament protein levels in patients with either MYBPC3 - or MYH7- mediated HCM suggest a poison peptide mechanism. Specifically, the mechanism of dysfunction may vary according to the genetic subgroup suggested by a distinctly abnormal distribution of myofilament proteins in patients manifesting a truncation mutation in MYBPC3 .

Background and Purpose— Embolic events have long been thought to occur in patients with cardiac tumors secondary to embolization of tumor fragments; however, there are no large studies examining the epidemiology and occurrence of embolism in this group of patients. Methods— From 1957 to 2006, 323 consecutive patients with primary cardiac tumors were treated surgically at our institution. Of these, patients who experienced an embolic event included 80 (cerebrovascular accident 31 [9.7%], transient ischemic attack 30 [9.3%], and other 19 [6%]). Those with no history of an embolic event (n=243 [75%]) were defined as control subjects. Results— Age was similar between the case and control groups (mean 54.5 versus 53.9 years, P =0.8). A multivariate logistic regression model including tumor location, tumor burden, tumor histology, and cerebrovascular risk factors, indicated that left atrial tumors (OR, 1.95; P =0.04), aortic valve tumors (OR, 4.17; P =0.002), and smaller tumor burden (OR, 2.20; P =0.01) were the most significant factors in the occurrence of embolism ( P <0.001). The presence of mitral regurgitation (OR, 0.12; P =0.006) and decreased functional status (New York Heart Association III/IV; OR, 0.31; P <0.001) were protective against the occurrence of embolism. Follow-up was obtained in 82% at a mean follow-up time of 6.17±6.9 years. There were no recurrent embolic events at follow-up. A Kaplan-Meier survival curve demonstrated no difference in survival between both groups ( P =0.78). Conclusion— Aortic valve and left atrial tumors have the greatest anatomic risk for embolism. Furthermore, patients with smaller tumors, minimal symptomatology, and no evidence of mitral regurgitation have a high risk of embolism. Cardiac tumors can be resected with low early mortality, and late survival after operation in the context of an embolic event is similar to patients with cardiac tumors who undergo resection for other indications.

Background— Primary cardiac tumors are rare but have the potential to cause significant morbidity if not treated in an appropriate and timely manner. To date, however, there have been no studies examining survival characteristics of patients who undergo surgical resection. Methods and Results— From 1957 to 2006, 323 consecutive patients underwent surgical resection of primary cardiac tumors; 163 (50%) with myxomas, 83 (26%) with papillary fibroelastomas, 18 (6%) with fibromas, 12 (4%) with lipomas, 28 (9%) with other benign primary cardiac tumors, and 19 (6%) with primary malignant tumors. Operative (30 day) mortality was 2% (n=6). Univariate analysis indicated that patients who underwent resection of fibromas and myxomas had superior survival characteristics in comparison to the remainder of tumor variants; these results were consistent after adjusting for age at surgery, year of surgery, and cardiovascular risk factors. Based on actuarial characteristics of the 2002 U.S. population, patients who underwent myxoma resection had survival characteristics that were not significantly different from that of an age and gender matched population (SMR 1.11, P =0.57) whereas those who underwent resection of fibromas (SMR 11.17, P =0.002), papillary fibroelastomas (SMR 3.17, P =0.0003), lipomas (SMR 5.0, P =0.0003), other benign tumors (SMR 4.63, P =0.003), and malignant tumors (SMR 101, P <0.0001) had significantly poorer survival characteristics. Furthermore, malignant tumors in younger patients were highly fatal (HR 0.899, P <0.0001). Although the most significant predictor of mortality was tumor histology, survival was also influenced the by the duration of CPB and NYHA III/IV; the impact of these risk factors varied with time. The cumulative incidence of myxoma recurrence was 13% and occurred in a younger population (42 versus 57 years, P =0.003) with the risk of recurrence decreased after 4 years. Conclusions— Surgical resection of primary cardiac tumors is associated with excellent long-term survival; patients with cardiac myxomas have survival characteristics that are not significantly different from that of a general population. Predictors of mortality are primarily related to tumor histology but also include clinical characteristics such as symptomatology and duration of CPB.

Background— This study evaluated long-term results of aortic root replacement and valve-preserving aortic root reconstruction for patients with aneurysms involving the aortic root. Methods and Results— Two-hundred three patients aged 53±16 years (mean±SD; 153 male, 50 female) underwent elective or urgent aortic root surgery from 1971 to 2000 for an aortic root aneurysm: 149 patients underwent a composite valve conduit reconstruction, and 54 patients underwent valve-preserving aortic root reconstruction. Fifty patients had Marfan syndrome. In-hospital and 30-day mortality was 4.0% (8/203) overall: for a composite valve conduit procedure, the corresponding value was 4.0% (6/149) and for valve-preserving procedure, 3.7% (2/54) ( P =NS). Morbidity included 3 strokes (1%), 10 perioperative myocardial infarctions (5%), and 8 reoperations for bleeding (4%). Actuarial survival at 5, 10, 15, and 20 years was 93% (95% confidence interval [CI] = 88% to 97%), 79% (95% CI = 71% to 87%), 67% (95% CI = 57% to 79%), and 52% (95% CI = 36% to 69%), respectively. Freedom from reoperation was 72% (95% CI = 54% to 86%) at 20 years. Complications with anticoagulation occurred in 29 patients; with valve thrombosis, in 2; and with hemorrhage, in 27 (4 life threatening and 23 minor). Freedom from thromboembolism was 91% (95% CI = 77% to 98%) at 20 years. Freedom from endocarditis was 99% (95% CI = 92% to 100%) at 20 years. Multivariate analysis revealed preoperative mitral valve regurgitation (+3 to 4) and older age to be significant predictors of late death ( P ≤0.005), and Marfan syndrome, initial valve-preserving aortic root reconstruction, and need for a concomitant procedure at initial operation to be significant predictors of the need for reoperation ( P ≤0.01). Conclusions— Aortic root replacement for aortic root aneurysms can be done with low morbidity and mortality. Composite valve conduit reconstruction resulted in a durable result. There were few serious complications related to the need for long-term anticoagulation or a prosthetic valve. Reoperation was most commonly required because of failure of the aortic valve when a valve-preserving aortic root reconstruction was performed or for other cardiac or aortic disease elsewhere.