Harish Ramakrishna

A core review of temperature regimens and neuroprotection during cardiopulmonary bypass: Does rewarming rate matter?

Despite a half century of research and the implementation of various risk-reduction strategies among clinicians and basic scientists, patients continue to experience strokes and cognitive dysfunction related to the use of cardiopulmonary bypass (CPB) for cardiac surgery. One strategy to reduce these detrimental effects has been the use of hypothermia. Although numerous studies have addressed the issue, the question of whether the use of hypothermia during CPB attenuates the impact of central nervous system consequences remains unresolved. However, data clearly demonstrate that hyperthermia is to be avoided in the perioperative period, necessitating careful rewarming strategies if hypothermia is used during CPB. Selecting and understanding the impact of the temperature-monitoring site is important to accurately estimate cerebral temperature and to avoid inadvertent surges in brain temperature. In this article, we review the literature regarding the impact of hypothermia and rewarming rates during cardiac surgery.

The Year in Cardiothoracic and Vascular Anesthesia: Selected Highlights From 2009

The hybrid operating room is the venue for transcatheter therapy with the convergence of 3 specialties: cardiac surgery, cardiovascular anesthesiology, and interventional cardiology. Transcatheter aortic valve replacement is proof that cardiac specialists have embraced the endovascular revolution. Because pharmacologic conditioning and ischemic myocardial conditioning are safe and effective, they are currently the focus of multiple trials. Angiotensin blockade, anemia, and endoscopic saphenous vein harvesting worsen outcome after coronary artery bypass graft (CABG) surgery. Although off-pump CABG surgery is equivalent to on-pump CABG surgery, it may improve outcomes in high-risk groups. Although percutaneous coronary intervention (PCI) significantly decreases mortality after myocardial infarction, the evidence is less convincing for intra-aortic balloon counterpulsation. Even though prasugrel recently was approved for platelet blockade in PCI, it may be superseded by ticagrelor. Although PCI and CABG surgery appear equivalent for multivessel coronary disease, CABG surgery lowers revascularization rates and also has superior outcomes in diabetics and the elderly. Hetastarch and N-acetylcysteine both increase bleeding and transfusion in cardiac surgery. Factor VII can treat life-threatening bleeding, but its safety requires further evaluation. Because eltrombopag and romiplostim stimulate platelet production, they may have a future role in hemostasis after cardiac surgery. Even though fenoldopam, atrial natriuretic peptide, and sodium bicarbonate are nephroprotective, further trials must confirm these findings. Intensive insulin therapy offers no further outcome advantage and significantly increases hypoglycemic risk. The past year has witnessed the advent of a new clinical venue, new devices, and new drugs. The coming year will most likely advance these achievements.

Challenges After the First Decade of Transcatheter Aortic Valve Replacement: Focus on Vascular Complications, Stroke, and Paravalvular Leak

Transcatheter aortic valve replacement (TAVR) is entering its second decade. Three major clinical challenges have emerged from the first decade of experience: vascular complications, stroke, and paravalvular leak (PVL). Major vascular complications remain common and independently predict major bleeding, transfusion, renal failure, and mortality. Although women are more prone to vascular complications, overall they have better survival than men. Further predictors of major vascular complications include heavily diseased femoral arteries and operator experience. Strategies to minimize vascular complications include a multimodal approach and sleeker delivery systems. Although cerebral embolism is very common during TAVR, it mostly is asymptomatic. Major stroke independently predicts prolonged recovery and increased mortality. Identified stroke predictors include functional disability, previous stroke, a transapical approach, and atrial fibrillation. Embolic protection devices are in development to mitigate the risk of embolic stroke after TAVR. PVL is common and significantly decreases survival. Undersizing of the valve prosthesis can be minimized with 3-dimensional imaging by computed tomography or echocardiography to describe the elliptic aortic annulus accurately. The formal grading of PVL severity in TAVR is based on its percentage of the circumferential extent of the aortic valve annulus. Further emerging management strategies for PVL include a repositionable valve prosthesis and transcatheter plugging. The first decade of TAVR has ushered in a new paradigm for the multidisciplinary management of valvular heart disease. The second decade likely will build on this wave of initial success with further significant innovations.

Perioperative Major Adverse Cardiovascular and Cerebrovascular Events Associated With Noncardiac Surgery

Importance Major adverse cardiovascular and cerebrovascular events (MACCE) are a significant source of perioperative morbidity and mortality following noncardiac surgery. Objective To evaluate national trends in perioperative cardiovascular outcomes and mortality after major noncardiac surgery and to identify surgical subtypes associated with cardiovascular events using a large administrative database of United States hospital admissions. Design, Setting, Participants Patients who underwent major noncardiac surgery from January 2004 to December 2013 were identified using the National Inpatient Sample. Main Outcomes and Measures Perioperative MACCE (primary outcome), defined as in-hospital, all-cause death, acute myocardial infarction (AMI), or acute ischemic stroke, were evaluated over time. Results Among 10 581 621 hospitalizations (mean [SD] patient age, 65.74 [12.32] years; 5 975 798 female patients 56.60%]) for major noncardiac surgery, perioperative MACCE occurred in 317 479 hospitalizations (3.0%), corresponding to an annual incidence of approximately 150 000 events after applying sample weights. Major adverse cardiovascular and cerebrovascular events occurred most frequently in patients undergoing vascular (7.7%), thoracic (6.5%), and transplant surgery (6.3%). Between 2004 and 2013, the frequency of MACCE declined from 3.1% to 2.6% (P for trend <.001; adjusted odds ratio [aOR], 0.95; 95% CI, 0.94-0.97) driven by a decline in frequency of perioperative death (aOR, 0.79; 95% CI, 0.77-0.81) and AMI (aOR, 0.87; 95% CI, 0.84-0.89) but an increase in perioperative ischemic stroke from 0.52% in 2004 to 0.77% in 2013 (P for trend <.001; aOR 1.79; CI 1.73-1.86). Conclusions and Relevance Perioperative MACCE occurs in 1 of every 33 hospitalizations for noncardiac surgery. Despite reductions in the rate of death and AMI among patients undergoing major noncardiac surgery in the United States, perioperative ischemic stroke increased over time. Additional efforts are necessary to improve cardiovascular care in the perioperative period of patients undergoing noncardiac surgery.

Atrial Fibrillation After Cardiac Surgery: Clinical Update on Mechanisms and Prophylactic Strategies

ATRIAL FIBRILLATION (AF) is a common complication after cardiac surgery and is associated with increased cost, morbidity, and mortality. Minimally invasive surgical techniques such as transcatheter aortic valve replacement (TAVR) have not substantially reduced the risk of developing AF. The development of AF after cardiac surgery remains common and significantly increases mortality, morbidity, and total hospital costs, including readmission. In an effort to reduce these adverse consequences of this complication, considerable research recently has focused on identifying prophylactic strategies for AF after cardiac surgery. A thorough understanding of the mechanisms underlying the genesis of AF in this setting may aid in designing preventative paradigms and standardizing treatment. The purpose of this expert review is to highlight the incidence, pathogenesis, and preventative strategies for AF after cardiac surgery.

Intravenous sub-anesthetic ketamine for perioperative analgesia

Ketamine, an N-methyl-d-aspartate antagonist, blunts central pain sensitization at sub-anesthetic doses (0.3 mg/kg or less) and has been studied extensively as an adjunct for perioperative analgesia. At sub-anesthetic doses, ketamine has a minimal physiologic impact though it is associated with a low incidence of mild psychomimetic symptoms as well as nystagmus and double vision. Contraindications to its use do exist and due to ketamines metabolism, caution should be exercised in patients with renal or hepatic dysfunction. Sub-anesthetic ketamine improves pain scores and reduces perioperative opioid consumption in a broad range of surgical procedures. In addition, there is evidence that ketamine may be useful in patients with opioid tolerance and for preventing chronic postsurgical pain.

Adult cardiac transplantation: A review of perioperative management Part - I

Heart transplant is the definitive therapy for end-stage heart failure. This two part review article focussed first on the perioperative management of patients for heart transplantation. This part II will be a comprehensive review of the current status of mechanical assist device therapy for surgical management of the patient with refractory end-stage heart failure.

A meta-analysis and meta-regression of long-term outcomes of transcatheter versus surgical aortic valve replacement for severe aortic stenosis

BACKGROUND Transcatheter aortic valve replacement (TAVR) has emerged as an alternative to surgical aortic-valve replacement (SAVR) for patients with severe symptomatic aortic stenosis (AS) who are at high operative risk. We sought to determine the long-term (≥1year follow-up) safety and efficacy TAVR compared with SAVR in patients with severe AS. METHODS A comprehensive search of PubMed, EMBASE, Cochrane Central Register of Controlled Trials, conference proceedings, and relevant Web sites from inception through 10 April 2016. RESULTS Fifty studies enrolling 44,247 patients met the inclusion criteria. The mean duration follow-up was 21.4months. No difference was found in long-term all-cause mortality (risk ratios (RR), 1.06; 95% confidence interval (CI) 0.91-1.22). There was a significant difference favoring TAVR in the incidence of stroke (RR, 0.82; 95% CI 0.71-0.94), atrial fibrillation (RR, 0.43; 95% CI 0.33-0.54), acute kidney injury (RR, 0.70; 95% CI 0.53-0.92), and major bleeding (RR, 0.57; 95% CI 0.40-0.81). TAVR had significant higher incidence of vascular complications (RR, 2.90; 95% CI 1.87-4.49), aortic regurgitation (RR, 7.00; 95% CI 5.27-9.30), and pacemaker implantation (PPM) (RR, 2.02; 95% CI 1.51-2.68). TAVR demonstrated significantly lower stroke risk compared to SAVR in high-risk patients (RR, 1.49; 95% CI 1.06-2.10); no differences in PPM implantation were observed in intermediate-risk patients (RR, 1.68; 95% CI 0.94-3.00). In a meta-regression analysis, the effect of TAVR baseline clinical features did not affect the long-term all-cause mortality outcome. CONCLUSION TAVR and SAVR showed similar long-term survival in patients with severe AS; with important differences in treatment-associated morbidity.

Comparison of local versus general anesthesia in patients undergoing transcatheter aortic valve replacement: A meta-analysis

Transcatheter aortic valve replacement (TAVR) is typically performed under general anesthesia (GA). However, there is increasing data supporting the safety of performing TAVR under local anesthesia/conscious sedation (LA). We performed a meta‐analysis to gain better understanding of the safety and efficacy of LA versus GA in patients with severe aortic stenosis undergoing TAVR.

Pulmonary Hypertension in Patients Undergoing Cardiac Surgery: Pathophysiology, Perioperative Management, and Outcomes

ULMONARY HYPERTENSION (PH) describes a vast array of disease states in which chronically elevated pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) ultimately result in right heart failure (RHF) and death. Cardiac surgical patients presenting with pre-existing PH are at a higher risk for postoperative complications. Accurate preoperative assessment and diligent anesthetic management are crucial for the best outcome. In this review, the authors describe the pathophysiology, preoperative assessment, and perioperative care including intravenous and inhaled therapies of PH in the patient undergoing cardiac surgery. Detailed discussions of the echocardiographic assessment of right ventricular (RV) function, perioperative risk factors, and outcomes of patients with PH also are included. CLASSIFICATION OF PH