Sivakumar Sivalingam

Bio: Sivakumar Sivalingam is an academic researcher from National Institutes of Health. The author has contributed to research in topics: Medicine & Cardiac surgery. The author has an hindex of 8, co-authored 43 publications receiving 185 citations.

Is it worth repairing rheumatic mitral valve disease in children? Long-term outcomes of an aggressive approach to rheumatic mitral valve repair compared to replacement in young patients

Abstract: OBJECTIVES Contemporary experience in mitral valve (MV) repair for children with rheumatic heart disease (RHD) is limited, despite the potential advantages of repair over replacement. We reviewed our long-term outcomes of rheumatic MV repair and compared them with the outcomes of MV replacement in children with RHD. METHODS This study is a review of 419 children (≤18 years) with RHD who underwent primary isolated MV surgery between 1992 and 2015, which comprised MV repair (336 patients; 80.2%) and MV replacement (83 patients; 19.8%). The replacement group included mechanical MV replacements (MMVRs) (n = 69 patients; 16.5%) and bioprosthetic MV replacements (n = 14 patients; 3.3%). The mean age with standard deviation at the time of operation was 12.5 ± 3.5 (2-18) years. Mitral regurgitation (MR) was predominant in 390 (93.1%) patients, and 341 (81.4%) patients showed ≥3+ MR. The modified Carpentier reconstructive techniques were used for MV repair. RESULTS Overall early mortality was 1.7% (7 patients). The mean follow-up was 5.6 years (range 0-22.3 years; 94.7% complete). Survival of patients who underwent repair was 93.9% both at 10 and 20 years, which was superior than that of replacement (P < 0.001). Freedom from reoperation at 10 and 20 years after MV repair was 81.7% and 72.6%, respectively, compared to 83.2% for MV replacement (P = 0.580). Forty patients underwent reoperation after the initial surgery with no operative deaths. Mixed mitral lesion and postoperative residual MR (≥2+) were the predictors for reoperation in the repair group, whereas lower body surface area and usage of bioprosthesis were significant factors for the replacement group. Freedom from thrombotic, embolic and haemorrhagic events at 10 and 20 years for patients with repair was 98.2% compared to 90.1% in patients with replacement and 67.6% for patients with MMVR (P = 0.004). CONCLUSIONS Twenty-three years of follow-up shows that MV repair is superior to MMVR in children with RHD. Hence, the rheumatic MV should be repaired when technically feasible to maximize the survival and reduce the valve-related morbidity with comparable durability to MMVR.

A Novel Restorative Pulmonary Valve Conduit: Early Outcomes of Two Clinical Trials.

Abstract: Objectives: We report the first use of a biorestorative valved conduit (Xeltis pulmonary valve-XPV) in children. Based on early follow-up data the valve design was modified; we report on the comparative performance of the two designs at 12 months post-implantation. Methods: Twelve children (six male) median age 5 (2 to 12) years and weight 17 (10 to 43) kg, had implantation of the first XPV valve design (XPV-1, group 1; 16 mm (n = 5), and 18 mm (n = 7). All had had previous surgery. Based on XPV performance at 12 months, the leaflet design was modified and an additional six children (five male) with complex malformations, median age 5 (3 to 9) years, and weight 21 (14 to 29) kg underwent implantation of the new XPV (XPV-2, group 2; 18 mm in all). For both subgroups, the 12 month clinical and echocardiographic outcomes were compared. Results: All patients in both groups have completed 12 months of follow-up. All are in NYHA functional class I. Seventeen of the 18 conduits have shown no evidence of progressive stenosis, dilation or aneurysm formation. Residual gradients of >40 mm Hg were observed in three patients in group 1 due to kinking of the conduit (n = 1), and peripheral stenosis of the branch pulmonary arteries (n = 2). In group 2, one patient developed rapidly progressive stenosis of the proximal conduit anastomosis, requiring conduit replacement. Five patients in group 1 developed severe pulmonary valve regurgitation (PI) due to prolapse of valve leaflet. In contrast, only one patient in group 2 developed more than mild PI at 12 months, which was not related to leaflet prolapse. Conclusions: The XPV, a biorestorative valved conduit, demonstrated promising early clinical outcomes in humans with 17 of 18 patients being free of reintervention at 1 year. Early onset PI seen in the XPV-1 version seems to have been corrected in the XPV-2, which has led to the approval of an FDA clinical trial. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT02700100 and NCT03022708.

Excision of sympathetic ganglia and the rami communicantes with histological confirmation offers better early and late outcomes in Video assisted thoracoscopic sympathectomy

Abstract: Video-Assisted Thoracoscopic Sympathectomy (VATS) is an established minimally invasive procedure for thoracic sympathetic blockade in patients with hyperhidrosis, facial flushing and intractable angina. Various techniques using clips, diathermy and excision are used to perform sympathectomy. We present our technique of excision of the sympathetic chain with histological proof and the analysis of the early and late outcomes. We evaluated 200 procedures in 100 consecutive patients, who underwent Video Assisted Thoracoscopic Sympathectomy by a single surgeon in our centre between September 1996 to March 2007. All patients had maximum medical therapy prior to surgery and were divided into 3 groups based on indications, Group 1(hyperhidrosis: 48 patients), Group 2 (facial flushing: 26 patients) and Group 3(intractable angina: 26 patients). The demography and severity of symptoms for each group were analysed. The endpoints were success rate, 30 day mortality, complications and patient's satisfaction. 99 patients had bilateral VATS sympathectomy and 1 had unilateral sympathectomy. The conversion rate to open was 1(1%). All patients had successful removal of ganglia proven histologically with no perioperative mortality in our series. The complications included pneumothorax (5%), acute coronary syndrome (2%), transient Horner's syndrome (1%), transient paraesthesia (1%), wound infection (4%), compensatory hyperhidrosis (18%), residual flushing (3%) and wound pain (5%). There were five late deaths in the intractable angina group at a mean follow up of 36.7 months. Overall success rates of abolishing the symptoms were 96.3%, 87.5% and 95.2% for Group 1, 2 and 3 respectively. Excision of the sympathetic chain with histological confirmation during VATS sympathectomy is a safe and effective method in treating hyperhidrosis, facial flushing and intractable angina with good long term results and satisfaction.

Contemporary long-term outcomes of an aggressive approach to mitral valve repair in children: is it effective and durable for both congenital and acquired mitral valve lesions?

Abstract: Objectives We analysed the long-term outcomes of mitral valve (MV) repair in children and compared the repairs for both congenital and acquired lesions. Methods A review of 634 children (≤18 years) who underwent MV repair from 1992 to 2011 was conducted [excluding patients with complete atrioventricular septal defect (AVSD), single ventricle and atrioventricular (AV) discordance]. Associated cardiac anomalies were present in 473 patients (75%). Congenital mitral lesions were found in 270 (43%) patients compared with an acquired aetiology in 364 (57%) [mainly rheumatic: 329 patients (90%)]. Mitral regurgitation (MR) was predominant in 606 (96%) patients, and 544 (86%) of these showed ≥3+ MR. Modified techniques of MV reconstructions were used. Results The early mortality rate was 2% (14 patients). The mean follow-up was 55 months (1-240 months; 85% complete). The late mortality rate was 4% (23 patients) and survival rates at 10 and 15 years were 91 and 86%, respectively. There was no significant difference in 10-year survival between repairing the congenital (98%) and acquired lesions (87%) (P = 0.17). The rate of freedom from reoperation after MV repair for the entire population was 79% at 10 years, with no significant difference between congenital (80%) and acquired lesions (79%) (P = 0.20). Fifty-six patients (9%) required reoperation. Mixed MV lesions, commissural fusions and residual MR (≥2+) were the predictors of valve failure and reoperation. All survivors remain in New York Heart Association class I and none had thromboembolism or pacemaker insertion. Conclusions MV repair can be successfully applied to both congenital and acquired MV disease in children. Aggressive repair techniques and avoidance of residual MR have improved durability and survival.

Best evidence topic - Cardiac general What is the optimal vasodilator for preventing spasm in the left internal mammary artery during coronary arterial bypass grafting?

Abstract: aa b, Summary A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was which (if any) vasodilator prevents spasm of the internal mammary artery in patients undergoing coronary artery bypass grafting. Two hundred papers were found using the reported search, of which 13 represented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses were tabulated. We conclude that mammary arteries often have low flow initially, but invariably will double their flow after 15-20 min even with no treatment. The strongest evidence for safe prevention of spasm is for papaverine given topically and periarterially, however many studies have also shown no benefit and thus no treatment at all is an entirely acceptable strategy. 2005 Published by European Association for Cardio-Thoracic Surgery. All rights reserved.

Integrated Smart Janus Textile Bands for Self-Pumping Sweat Sampling and Analysis.

Abstract: Wearable sweat sensors have spearheaded the thrust toward personalized health monitoring with continuous, real-time, and molecular-level insight in a noninvasive manner. However, effective sweat sampling still remains a huge challenge. Here, we introduce an intelligent Janus textile band that bridges the gap between self-pumping sweat collection, comfortable epidemic microclimate, and sensitive electrochemical biosensing via an integrated wearable platform. The dominant sweat sampling configuration is a textile with Janus wettability, which is fabricated by electrospinning a hydrophobic polyurethane (PU) nanofiber array onto superhydrophilic gauze. Based on a contact-pumping model, the Janus textile can unidirectionally and thoroughly transport sweat from skin (hydrophobic side) to embedded electrode surface (hydrophilic side) with epidemic comfort. On-body experimentation reveals that the sensitive detection of multiple biomarkers including glucose, lactate, K+, and Na+ is achieved in the pumped sweat. Such smart Janus textile bands can effectively drain epidermal sweat to targeted assay sites via interface modifications, representing a reinforced and controlled biofluids analysis pathway with physiological comfort.

Tissue engineering strategies for the induction of angiogenesis using biomaterials

Abstract: Angiogenesis is touted as a fundamental procedure in the regeneration and restoration of different tissues. The induction of de novo blood vessels seems to be vital to yield a successful cell transplantation rate loaded on various scaffolds. Scaffolds are natural or artificial substances that are considered as one of the means for delivering, aligning, maintaining cell connection in a favor of angiogenesis. In addition to the potential role of distinct scaffold type on vascularization, the application of some strategies such as genetic manipulation, and conjugation of pro-angiogenic factors could intensify angiogenesis potential. In the current review, we focused on the status of numerous scaffolds applicable in the field of vascular biology. Also, different strategies and priming approaches useful for the induction of pro-angiogenic signaling pathways were highlighted.

Contemporary Diagnosis and Management of Rheumatic Heart Disease: Implications for Closing the Gap: A Scientific Statement From the American Heart Association.

Abstract: The global burden of rheumatic heart disease continues to be significant although it is largely limited to poor and marginalized populations. In most endemic regions, affected patients present with heart failure. This statement will seek to examine the current state-of-the-art recommendations and to identify gaps in diagnosis and treatment globally that can inform strategies for reducing disease burden. Echocardiography screening based on World Heart Federation echocardiographic criteria holds promise to identify patients earlier, when prophylaxis is more likely to be effective; however, several important questions need to be answered before this can translate into public policy. Population-based registries effectively enable optimal care and secondary penicillin prophylaxis within available resources. Benzathine penicillin injections remain the cornerstone of secondary prevention. Challenges with penicillin procurement and concern with adverse reactions in patients with advanced disease remain important issues. Heart failure management, prevention, early diagnosis and treatment of endocarditis, oral anticoagulation for atrial fibrillation, and prosthetic valves are vital therapeutic adjuncts. Management of health of women with unoperated and operated rheumatic heart disease before, during, and after pregnancy is a significant challenge that requires a multidisciplinary team effort. Patients with isolated mitral stenosis often benefit from percutaneous balloon mitral valvuloplasty. Timely heart valve surgery can mitigate the progression to heart failure, disability, and death. Valve repair is preferable over replacement for rheumatic mitral regurgitation but is not available to the vast majority of patients in endemic regions. This body of work forms a foundation on which a companion document on advocacy for rheumatic heart disease has been developed. Ultimately, the combination of expanded treatment options, research, and advocacy built on existing knowledge and science provides the best opportunity to address the burden of rheumatic heart disease.