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Biomedical subjects

Shahzad G Raja

Publications and source records attributed to Shahzad G Raja.

At least 19 recordsLinked to original sources
PubMed2006

Drug-eluting stents and the future of coronary artery bypass surgery: facts and fiction.

The treatment of patients with coronary artery disease continues to evolve. Recent, exciting data on the use of drug-eluting stents in diseased coronary vessels has generated immense enthusiasm within the interventional community leading to claims that "drug-eluting stents will put bypass surgeons out of business." However, despite promising short-term and midterm outcomes of this revolutionary new technology, valid concerns regarding long-term safety and efficacy of drug-eluting stents persist. This review article evaluates current status of drug-eluting stents with special emphasis on real and potential drawbacks of this emerging percutaneous coronary interventional modality and its impact on the practice of coronary artery bypass surgery.

Cardiovascular Agents↗
PubMed2006

Levosimendan in cardiac surgery: current best available evidence.

Recent upsurge in referral of patients with high perioperative risk or compromised left ventricular function for cardiac surgery has lead to an increasing use of pharmacologic support in the form of vasodilator and inotropic therapy to achieve improvement of tissue perfusion in the perioperative period or to support weaning from cardiopulmonary bypass. Traditionally, perioperatively used inotropic agents, epinephrine, dobutamine, and milrinone, are limited by significant increases in myocardial oxygen consumption, proarrhythmia, or neurohormonal activation. Levosimendan, a new inodilator for the treatment of decompensated heart failure, has also shown promise in elective therapy of cardiac surgical patients with high perioperative risk or compromised left ventricular function, as well as in rescue therapy of patients with difficult weaning from cardiopulmonary bypass. This review article briefly discusses the pharmacology of levosimendan and evaluates current best available evidence to assess the safety and efficacy of levosimendan usage in cardiac surgery.

Adult↗
PubMed2006

Impact of off-pump coronary artery bypass surgery on postoperative renal dysfunction: current best available evidence.

Renal dysfunction is a serious complication after coronary artery bypass surgery with cardiopulmonary bypass. Cardiopulmonary bypass-related non-pulsatile flow, hypothermia, haemolysis, systemic inflammatory reactions and emboli are mentioned as possible causes for this postoperative renal dysfunction. In an attempt to avoid these deleterious effects of cardiopulmonary bypass, off-pump coronary artery bypass surgery has been rediscovered. Resurgence of interest in off-pump coronary artery bypass surgery is associated with the expectation that avoiding deleterious effects of the cardiopulmonary bypass leads to better outcomes and possibly decreased costs and resource use. We are currently practising in an era of evidence-based medicine that mandates the prospective randomized controlled trial as the most accurate tool for determining a treatment benefit compared with a control population. The present review article attempts to evaluate the current best available evidence from randomized controlled trials on the impact of off-pump coronary artery bypass surgery on postoperative renal dysfunction.

Coronary Artery Bypass, Off-Pump↗
PubMed2006

Impact of modified ultrafiltration on morbidity after pediatric cardiac surgery.

Cardiopulmonary bypass is a double-edged sword. Without it, corrective cardiac surgery would not be possible in the majority of children with congenital heart disease. However, much of the perioperative morbidity that occurs after cardiac surgery can be attributed to a large extent to pathophysiologic processes engendered by extracorporeal circulation. One of the challenges that has confronted pediatric cardiac surgeons has been to minimize the consequences of cardiopulmonary bypass. Ultrafiltration is a strategy that has been used for many years in an effort to attenuate the effects of hemodilution that occur when small children undergo surgery with cardiopulmonary bypass. Over the past several years, a modified technique of ultrafiltration, commonly known as modified ultrafiltration, has been used with increasing enthusiasm. Multiple studies have been undertaken to assess the effects of modified ultrafiltration on organ function and postoperative morbidity following repair of congenital heart defects. This review attempts to evaluate current available scientific evidence on the impact of modified ultrafiltration on organ function and morbidity after pediatric cardiac surgery.

Cardiac Surgical Procedures↗
PubMed2006

Composite arterial grafting.

The success of coronary artery bypass grafting, the gold standard for the treatment of multivessel coronary artery disease, is limited by poor long-term vein-graft patency. By contrast, the left internal mammary artery has been demonstrated to have a superior graft patency rate and has provided excellent clinical results. This suggests that the use of arterial conduits for coronary artery bypass grafting may be beneficial for long-term results. Recently, there has been an upsurge in the use of arterial grafts for myocardial revascularization based on the clinical advantage of the use of the left internal mammary artery as a bypass conduit. Many retrospective studies have supported the safety and the effectiveness of arterial grafting, and it has become apparent that the free arterial graft can be used as a branched or a lengthened conduit to the in situ arterial graft by adopting one or more of the several composite grafting techniques. Arterial composite grafts with or without sequential grafting techniques appear an attractive strategy as increased number of distal coronary anastomoses can be performed, with a limited number of grafts, avoiding proximal aortic anastomoses. However, concerns regarding the total dependence of the coronary bypass flow on the flow of one in situ arterial graft and technical error, resulting in compromised flow in one or both limbs of the composite graft have prevented composite arterial grafting from being universally adopted. It is expected that in the near future a prospective, multi-institutional, randomized controlled trial, to compare the short- and long-term outcomes of exclusive arterial grafting using composite and conventional aortocoronary revascularization strategies, will be undertaken to validate the safety and efficacy of composite arterial grafting.

Arteries↗
PubMed2006

Contegra conduit: current outcomes and concerns.

A variety of congenital cardiac anomalies with severe right ventricular outflow tract (RVOT) obstruction or RVOT interruption require surgical reconstruction from the infundibulum up to the pulmonary artery bifurcation or even into the branches of the pulmonary arteries. Ideally, the conduit or valve required for such reconstruction has to be formed of autologous tissue that grows, resists infection, lasts for the life span of the patient and is readily available in all sizes. Such conduits, however, are not available and although several alternatives have been used, none of which are without potential drawbacks. Contegra valved bovine internal jugular vein conduit (Medtronic Inc., MN, USA) has recently emerged as a promising option for pediatric RVOT reconstruction and has been advocated for its 'off-the-shelf' availability in sizes ranging from 12 to 22 mm, surgical pliability and encouraging short- and mid-term success in experimental animal, as well as clinical studies. This review focuses on the current outcomes of Contegra conduit and highlights some of the major concerns related to the use of this conduit and strategies to tackle these concerns.

Animals↗
PubMed2006

Cardioprotection with sildenafil: implications for clinical practice.

Myocardial ischemia-reperfusion injury occurs in a wide spectrum of patients, ranging from survivors of out-of-hospital cardiac arrest to acute myocardial infarction victims as well as patients undergoing cardiac surgery, and represents a major public health burden. This injury contributes significantly to morbidity and mortality, despite meticulous adherence to presently known principles of myocardial protection. Despite the considerable progress that has been made in the field of myocardial protection, high-risk subsets of patients continue to exhibit ischemia-reperfusion-related complications, including prolonged contractile dysfunction (stunning), low-output syndrome, perioperative myocardial infarction, and cardiac failure, requiring prolonged intensive care. Sildenafil, a phosphodiesterase 5 inhibitor, currently licensed for the treatment of erectile dysfunction and pulmonary hypertension has shown great promise in animal studies as a possible pharmacologic agent for cardioprotection. This review article discusses the pharmacology of sildenafil and focuses on the available evidence from animal studies on the potential role of sildenafil for treating ischemia-reperfusion injury with its implications for clinical practice.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2005

Internal thoracic artery: to skeletonize or not to skeletonize?

The internal thoracic artery has been the most reliable graft material used in coronary artery bypass grafting with an excellent long-term patency rate. Complete myocardial revascularization with internal thoracic arteries improves long-term survival and decreases the rate of repeat operations compared with vein grafts. Adequate length of the graft in coronary artery bypass graft surgery is essential for providing complete arterial revascularization. In the last decade or so, technique of skeletonization of internal thoracic artery has been proposed to achieve extra length. Skeletonization of the internal thoracic artery allows the preparation of longer conduits with a superior free flow and can reduce the incidence of postoperative pulmonary and sternal complications. However, concerns about vasoreactivity of skeletonized internal thoracic artery grafts, the functional consequences of surgical trauma, the possible loss of innervation, and vasa vasorum perfusion in the skeletonized conduits have prevented this technique from being universally accepted. Presently available evidence from retrospective studies (level 3 evidence) suggests that skeletonization is a safe and effective technique for myocardial revascularization. However, there is a need for conducting multicenter, randomized controlled trials comparing the skeletonized and pedicled internal thoracic arteries with special emphasis on long-term patency to conclusively validate the safety and efficacy of skeletonization technique.

Angioplasty, Balloon, Coronary↗