Manoraj Navaratnarajah

Continuous in vivo blood pressure measurements using a fully implantable wireless SAW sensor

In this paper, the development of a fully implantable wireless sensor able to provide continuous real-time accurate pressure measurements is presented. Surface Acoustic Wave (SAW) technology was used to deposit resonators on crystalline quartz wafers; the wafers were then assembled to produce a pressure sensitive device. Excitation and reading via a miniature antenna attached to the pressure sensor enables continuous external interrogation. The main advantages of such a configuration are the long term stability of quartz and the low power necessary for the interrogation, which allows 24/7 interrogation by means of a hand-held, battery powered device. Such data are of vital importance to clinicians monitoring and treating the effects of hypertension and heart failure. A prototype was designed and tested using both a bio-phantom test rig and an animal model. The pressure traces for both compare very well with a commercially available catheter tip pressure transducer. The work presented in this paper is the first known wireless pressure data from the left ventricle of the heart of a living swine.

Impact of Minimal Access Valve Surgery on Clinical Outcomes: Current Best Available Evidence

Abstract  Recent years have seen a surge in the enthusiasm to perform minimal access valve surgery to reduce morbidity and improve clinical outcomes. Despite tremendous enthusiasm on the part of proponents of minimal access valve surgery, skepticism still exists about the actual impact of minimal access valve surgery in reducing postoperative morbidity. This review article attempts to evaluate the current best available evidence on the impact of minimal access valve surgery on postoperative clinical outcomes. Methods: The English language scientific literature was reviewed primarily by searching Medline from 1966 through February 2008 using PubMed interface. All blinded or unblinded randomized clinical trials, comparing minimal access valve surgery with conventional valve surgery through a full sternotomy, recruiting adult human patients undergoing valve repair, or replacement and reporting impact of these two approaches on at least 1 pertinent clinical or economic outcome, were included. Results: Current best available evidence from randomized clinical trials (Grade A, Level 1b) does not show any significant quantitative differences between minimal access valve surgery and conventional valve surgery for perioperative mortality or other primary outcome events of stroke, renal failure, or respiratory failure. There are small but statistically significant benefits for minimal access valve surgery for surrogate outcomes of ventilation time, intensive care unit stay, and total length of stay. Conclusion: The published evidence is thin and a large multicenter randomized clinical trial with preferably standardization of minimal access valve surgery techniques and long term follow‐up is required to validate the safety and efficacy of minimal access valve surgery.

Treatment of high-output coronary artery fistula by off-pump coronary artery bypass grafting and ligation of fistula

Coronary artery fistulas (CAF) are uncommon entities often associated with myocardial ischemia and high output failure. Surgical options include ligation of the fistula, with/without simultaneous coronary artery bypass grafting (CABG). We report a case of left main coronary artery (LMCA) fistula to the coronary sinus (CS), which was associated with high-output bi-ventricular failure, and moderate mitral (MR) and tricuspid regurgitation (TR), related to the volume overload and annular dilatation. This was tackled elegantly by off-pump CABG to protect the territories supplied by the LMCA, followed by ligation of the fistula. This resulted in resolution of the MR and TR. Intraoperative transesophageal echocardiogram (TEE) greatly facilitated the surgical treatment, by identifying the origin and the draining points for the fistula, and aided in the quantification of MR and TR, which had regressed sufficiently at the end of the procedure and did not require surgical correction. This article outlines the importance of multi-disciplinary treatment approach for this complex condition.

In-hospital outcomes of pedicled bilateral internal mammary artery use in diabetic and nondiabetic patients undergoing off-pump coronary artery bypass grafting: single-surgeon, single-center experience.

OBJECTIVE A common perception is that use of pedicled bilateral internal mammary arteries (BIMA) increases the risk of sternal wound complications in diabetic patients undergoing coronary artery bypass grafting (CABG). The purpose of this study was to compare the in-hospital outcomes of CABG using pedicled BIMA in diabetic and nondiabetic patients. METHODS From September 1998 to September 2010, 390 consecutive diabetic patients and 519 nondiabetic patients underwent isolated off-pump CABG using pedicled BIMA. The 2 groups had comparable preoperative demographics except for a higher prevalence of acute myocardial infarction (18.9% versus 6.1%, P = .01), peripheral vascular disease (17.2% versus 2.7%, P = .001), an ejection fraction <30% (17.7% versus 8.5%, P = .02), and chronic renal failure (4.5% versus 0.9%, P = .01) in the diabetic patients. RESULTS The operative mortality rate of the diabetic patients was comparable to that of the nondiabetic patients (2.8% versus 2.1%, P = .87). The in-hospital outcomes, including occurrence of superficial and deep sternal wound infections, were similar except for an increased occurrence of wound infection at the vein harvest site (6.6% versus 1.1%, P = .04) and a need for hemofiltration (11.8% versus 2.1%, P = .02) in the diabetic patients. CONCLUSIONS Pedicled BIMA use is associated with comparable incidences of sternal wound complications and other outcomes in diabetic patients and nondiabetic patients. Strict perioperative glycemic control, adherence to meticulous closure technique, and postoperative management of surgical wounds can make pedicled BIMA use a default strategy for diabetic patients.

Concomitant Off-Pump Coronary Artery Bypass Grafting Results in Improved In-Hospital Outcomes for Patients with Ischemic Mitral Regurgitation Undergoing Surgery

OBJECTIVE Surgical management of ischemic mitral regurgitation (IMR) has primarily consisted of revascularization with or without the addition of mitral valve repair or replacement. We hypothesize that performing off-pump coronary artery bypass (OPCAB) grafting before fixing MR improves in-hospital outcomes for patients with IMR undergoing surgery. METHODS From January 2000 through December 2010, a total of 96 consecutive patients with moderate or severe IMR, as determined by preoperative echocardiography, underwent on-pump coronary artery bypass grafting (CABG) (n = 66) or OPCAB (n = 30) revascularization with concomitant mitral valve repair or replacement. A retrospective analysis of a prospectively collected cardiac surgery database (PATS; Dendrite Clinical Systems, Oxford, UK) was performed. In addition, medical notes and charts were reviewed for all study patients. RESULTS The 2 groups had similar preoperative demographic and EuroSCORE risk-stratification characteristics. The operative mortality rate for the entire cohort was 9.4%. Patients who underwent OPCAB grafting had a lower operative mortality than those who underwent CABG (3.3% versus 12.1%; P = .006). The mean ±SD cardiopulmonary bypass time (82.7 ± 34.7 minutes versus 160.7 ± 45.2 minutes; P < .001) and cross-clamp time (49.0 ± 22.4 minutes versus 103.4 ± 39.5 minutes; P < .001) were significantly shorter in the off-pump group than in the on-pump group. The OPCAB group also had significantly less in-hospital morbidity and shorter stays in the intensive care unit and the hospital. CONCLUSION Our analysis shows that OPCAB grafting (compared with conventional CABG) before repairing MR is associated with favorable in-hospital outcomes for patients undergoing surgery for IMR.

Large patent ductus arteriosus in an adult complicated by pulmonary endarteritis and embolic lung abscess

Patent ductus arteriosus in the adult is an extremely rare clinical phenomenon. We report the case of a 34-year old man who developed pulmonary endarteritis and subsequent embolic lung abscess secondary to a large patent ductus arteriosus. This brief report also provides an overview of the natural history, potential complications, optimal therapy, and diagnostic dilemmas associated with this persistent congenital cardiac defect in adults.

For patients undergoing coronary artery bypass grafting at higher risk of stroke is the single cross-clamp technique of benefit in reducing the incidence of stroke?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether, for patients undergoing coronary artery bypass grafting at higher risk of stroke, the single cross-clamp (SC) technique is of benefit in reducing the incidence of stroke. Using the reported search 458 papers were identified. Six randomised controlled trials (RCTs), of which one was a duplicate publication, represented the best evidence on the subject. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results and study comments and weaknesses were tabulated for these. We conclude that current best available evidence, from six RCTs randomising 490 patients, suggests that there is no benefit of SC technique over multiple cross-clamp (MC) technique in terms of reduction in the incidence of stroke (SC=2/206 vs. MC=7/284; P=ns) although there is some advantage of SC technique in causing less neuropsychological deficits and release of serum S-100 protein, a surrogate marker of cerebral injury.

Ten-year outcome analysis of off-pump sequential grafting: single surgeon, single center experience.

OBJECTIVES Despite increasing recognition that off-pump coronary artery bypass surgery and sequential grafting strategy individually are associated with improved outcomes, concerns persist regarding the safety and efficacy of combining these 2 techniques. We compared in-hospital and midterm outcomes for off-pump multivessel sequential and conventional coronary artery bypass grafting. METHODS From September 1998 to September 2008, 689 consecutive patients received off-pump multivessel sequential coronary artery bypass grafting performed by a single surgeon. These patients were propensity matched to 689 patients who underwent off-pump coronary artery bypass grafting without sequential anastomoses. A retrospective analysis of prospectively collected perioperative data was performed. In addition, medical notes and charts of all the study patients were reviewed. The mean duration of follow-up was 5.1 ± 2.0 years. RESULTS The major in-hospital clinical outcomes in the sequential and control groups were found to be similar. After adjusting for clinical covariates, sequential grafting was not an independent predictor of in-hospital adverse events (odds ratio [OR], 1.18; 95% confidence interval [CI], 0.86-1.50; P = .31), medium-term mortality (hazard ratio [HR], 1.26; 95% CI, 1.06-1.32; P = .92), and readmission to hospital (HR, 1.12; 95% CI, 0.96-1.20; P = .80). Sequential grafting was an independent predictor of receiving more than 3 distal anastomoses (OR, 7.46; 95% CI, 4.27-11.45; P < .0001). Risk-adjusted survival was 89% for sequential grafting patients and 88% for conventional grafting patients (P = .96) during the medium-term follow-up. CONCLUSION Our analysis confirms the short- and midterm safety and efficacy of off-pump sequential coronary artery bypass grafting.

10-Year Follow-Up of Off-Pump Multivessel Coronary Artery Bypass Grafting

On-pump total arterial grafting is associated with improved long-term outcomes compared to conventional grafting using left internal thoracic artery and saphenous vein grafts, but there are no data to confirm the same for off-pump total arterial grafting. We assessed the impact of off-pump total arterial grafting on medium-term outcomes. From September 1998 to September 2008, 580 consecutive patients who had off-pump multivessel arterial grafting only were compared with a control group of 806 patients undergoing off-pump coronary artery bypass with internal thoracic artery and saphenous vein grafts, performed by the same surgeon. Perioperative data were collected prospectively. Medium-term univariate and risk-adjusted comparisons between the 2 groups were carried out. After adjusting for clinical covariates, total arterial grafting did not emerge as a significant independent predictor of medium-term mortality, readmission to hospital, or the composite outcome of death and readmission. At medium-term follow-up, off-pump total arterial grafting, despite being a safe and effective myocardial revascularization strategy, offered no mortality or morbidity benefits.

Chylothorax and Chylopericardium Following Mitral and Tricuspid Valve Repairs and Radiofrequency Maze Procedure

Abstract  Surgical radiofrequency Maze procedure is a well‐developed technology with an established safety profile. Clinical complications, albeit rare, have been described secondary to usage of unipolar radiofrequency devices. Bipolar radiofrequency devices have virtually eliminated the complications associated with unipolar devices, thereby combining safety with efficacy. We report a case of chylopericardial tamponade and chylothorax following radiofrequency Maze procedure using a bipolar device. (J Card Surg 2011;26:279‐281)