Saurabh Sanon

Perioperative Cardiovascular Risk of Prior Coronary Stent Implantation Among Patients Undergoing Noncardiac Surgery

BACKGROUND Previous studies have observed high rates of perioperative cardiovascular events in patients with coronary stents undergoing noncardiac surgery (NCS). It is uncertain whether this finding reflects an independent association. OBJECTIVES The goal of this study was to assess the independent relationship between prior coronary stent implantation and the occurrence of perioperative major adverse cardiac and cerebrovascular events (MACCE) and bleeding and its relation with time from stenting to NCS. METHODS A total of 24,313 NCS cases at the Mayo Clinic (Rochester, Minnesota) from 2006 through 2011 were included in the study; 1,120 (4.6%) cases involved patients with coronary stents. MACCE was defined as death, myocardial infarction, cardiac arrest, or stroke. Age-adjusted odds ratios (aORs) were calculated after propensity adjustment for Revised Cardiac Risk Index factors and other conventional risk factors. RESULTS The 30-day MACCE rates were 3.7% and 1.5% in stented and unstented patients, respectively (p < 0.001). The risk of MACCE was largely related to the time from stent implantation to NCS, indicating substantially elevated risk in the first year after stenting (aOR: 2.59; 95% confidence interval [CI]: 1.36 to 4.94) but not thereafter (aOR: 0.89; 95% CI: 0.59 to 1.36). Bleeding displayed a similar pattern, indicating elevated risk in the first year after stenting (aOR: 2.23; 95% CI: 1.55 to 3.21) but not thereafter (aOR: 1.07; 95% CI: 0.89 to 1.28). Subgroup analysis in patients with known stent type found that the increased risk of both MACCE and bleeding >1 month after stent implantation was not limited to only those with drug-eluting stents. CONCLUSIONS This study found that prior coronary stent implantation is an independent risk factor for MACCE and bleeding when time from stenting to NCS is <1 year, both in patients with bare-metal and drug-eluting stents.

Techniques and Outcomes for the Treatment of Paravalvular Leak

Paravalvular prosthetic regurgitation is a potentially serious condition resulting from degeneration of annular tissue, affecting 6% to 15% of surgically implanted prosthetic valves and annuloplasty rings.1–3 In conditions of tissue friability from any cause, annular calcification, or infection, paravalvular defects can form and lead to varying degrees of regurgitation. Surgical factors associated with the development of paravalvular regurgitation include prostheses in the mitral position, supra-annular aortic prostheses, use of continuous sutures in the mitral position,3 and use of sutures without pledgets.4 Paravalvular defects are often crescentic and irregular in shape and may follow a serpiginous track from the downstream to upstream chamber. Chronic paravalvular mitral and aortic regurgitation can lead to left ventricular (LV), left atrial (LA) volume, and pressure overload, resulting in clinical heart failure. Because of noncompliance of the receiving chamber, the volume of regurgitation needed to induce symptoms may be relatively modest, such that standard volumetric measurements of regurgitation severity may not be applicable. In addition, conventional measures of mitral regurgitation severity such as the proximal isovelocity surface area method or pulmonary venous Doppler lack validation in this setting. Secondary elevation in pulmonary arterial pressure may result in right-sided heart failure. Paravalvular regurgitation is the most common cause of hemolytic anemia in patients with prosthetic heart valves. Increased red blood cell shear stress because of turbulent flow through the defect causes mechanical trauma and red blood cell fragmentation. Clinically significant hemolysis is more common in smaller defects with high-velocity jets, in patients with increased red blood cell fragility because of iron and folate deficiency, and in those with preexisting anemia because of the increased turbulence occurring from reduced blood viscosity and increased cardiac output. Moderate to severe paravalvular leak (PVL) after both surgical and transcatheter aortic valve replacement is associated with increased …

Hypoglycemia From a Cardiologist's Perspective

Hypoglycemia in people with diabetes mellitus (DM) has been potentially linked to cardiovascular morbidity and mortality. Pathophysiologically, hypoglycemia triggers activation of the sympathoadrenal system, leading to an increase in counter‐regulatory hormones and, consequently, increased myocardial workload and oxygen demand. Additionally, hypoglycemia triggers proinflammatory and hematologic changes that provide the substrate for possible myocardial ischemia in the already‐diseased diabetic cardiovascular system. Hypoglycemia creates electrophysiologic alterations causing P‐R–interval shortening, ST‐segment depression, T‐wave flattening, reduction of T‐wave area, and QTc‐interval prolongation. Patients who experience hypoglycemia are at an increased risk of silent ischemia as well as QTc prolongation and consequent arrhythmias. The Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial showed an increase in all‐cause mortality with intensive glycemic control, whereas the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) study and Veterans Affairs Diabetes Trial (VADT) showed no benefit with aggressive glycemic control. Women, elderly patients, and those with renal insufficiency are more vulnerable to hypoglycemic events. In fact, hypoglycemia is the most common metabolic complication experienced by older patients with DM in the United States. The concurrent use of medications like β‐blockers warrants caution in DM because they can mask warning signs of hypoglycemia. Here we aim to elucidate the pathophysiology, review the electrocardiographic changes, analyze the current clinical literature, and consider the safety considerations of hypoglycemia as it relates to the cardiovascular system. In conclusion, in the current era of DM and its vascular ramifications, hypoglycemia from a cardiologists perspective deserves due attention.

Continuous Left Atrial Pressure Monitoring During MitraClip: Assessing the Immediate Hemodynamic Response

We describe the novel use of continuous left atrial pressure (LAP) monitoring to guide the MitraClip (Abbott Vascular, Santa Clara, California) procedure. In addition to transesophageal echocardiography, we have found that direct measurement of LAP is also a useful tool to determine the hemodynamic

Hydrophilic polymer embolism induced acute transcatheter aortic valve thrombosis: A novel complication

Hydrophilic polymer coated introducer sheaths and medical devices are widely used in interventional cardiology. Despite the potential procedural advantages that these provide, a risk of polymer embolization has been recently reported. We describe the first reported case of hydrophilic polymer induced acute transcatheter aortic valve thrombosis.

Imaging of Vulnerable Plaques Using Near-Infrared Spectroscopy for Risk Stratification of Atherosclerosis

Although the prevalent approach in cardiology is largely “stenosis-centric,” it has been long known that most acute coronary events are caused by apparently angiographically nonsignificant stenosis. This has led to a gradual paradigm shift from detection of significant stenosis to detection of lesion instability. A number of imaging modalities have been developed that help in this quest; however, none have been as promising as near-infrared spectroscopy used for detection of coronary plaque characteristics. In this article we discuss the various invasive imaging tools available to the interventional cardiologist, with special emphasis on near-infrared spectroscopy as a key emerging imaging technology.

Play of Chance Versus Concerns Regarding Dipeptidyl Peptidase-4 Inhibitors: Heart Failure and Diabetes

The delicate balance of disease management versus off-target effects of treatment continues to be a vital concern to both patients and physicians. This article offers a brief overview of heart failure in diabetes and comments on the recent outcome trials of dipeptidyl peptidase-4 (DPP-4) inhibitors, with a closer look at a few pathobiological concerns. The importance of safe antidiabetic treatments becomes apparent when one considers the increasing obesity and diabetes pandemics. Approximately 150,000 patients with moderate-high cardiovascular (CV) risk factor profiles are currently enrolled in trials of antidiabetic agents. Establishing the CV safety of newer antidiabetic agents, especially with respect to heart failure, remains crucial. Heart failure syndrome is a symptom complex composed of worsening shortness of breath, orthopnea, paroxysmal nocturnal dyspnea, fatigue, and the well-known manifestation of ankle edema. The syndrome is characterized by physical findings of fluid retention (dependent edema), a third heart sound, rales sounds, and distension of the neck veins. In addition, heart failure is associated with chronic inflammation and a prothrombotic state. Endothelial dysfunction and proteomic and neurohormonal activation occur many months before development of the syndrome complex.1,2 Newer areas of basic science research have identified potential prognostic indicators in chronic heart failure (miR126 and miR508-5p) that might be used as novel markers leading to earlier diagnosis and treatment of heart failure.3,4 Heart failure has several etiologies ranging from mechanical and electrical dysfunction to structural and valvular abnormities. Moreover, the consequences of heart failure are multi-systemic and adversely affect the liver, kidneys, bone marrow, and muscle. Recent data from the Olmstead County population study5 showed that patients with diabetes had equal amounts of systolic and diastolic dysfunction. Patients with diabetes frequently have preserved left-ventricular function (a normal ejection fraction) but with a poorly compliant left ventricle that is …

Percutaneous Transapical Access With Closure for Ventricular Tachycardia Ablation

In patients with mechanical aortic valve prosthesis undergoing left ventricular (LV) endocardial ablation, retrograde catheter access through the aortic valve carries an unacceptable risk of catheter entrapment and death, and the atrial trans-septal approach remains the only routinely used option. Because of the circuitous path required to reach subaortic and other LV regions via the trans-septal route, ablation catheter contact force may not be sufficient1 for successful energy delivery. Therefore, additional techniques for a more direct access to the LV may be advantageous, including ventricular trans-septal access,2 and transapical access via surgical mini-thoracotomy.3 Percutaneous transapical access to the LV combines the advantages of a direct LV access (abundance of catheter maneuverability and contact force needed for ablation energy delivery) with the convenience of a nonsurgical technique (performable in the electrophysiological laboratory). Growing experience with this approach and advances in available closure options after transapical sheath removal, allow for this technique to be implemented without the previously documented complications.3 ### Clinical History A 74-year-old man with ischemic cardiomyopathy and mechanical aortic prosthesis (29-mm bileaflet St. Jude valve placed at the age of 60 years) received recurrent shocks from his implantable cardioverter–defibrillator for monomorphic ventricular tachycardia (VT). Two previous ablations using a trans-septal puncture to access the LV failed to control the arrhythmia burden because of inadequate catheter contact with the basal LV septum, the critical arrhythmogenic substrate (Figure 1A). His coronary arteries were characterized by a codominant system with known right coronary artery in-stent stenosis (95%), which could not be percutaneous revascularized because of inability of the balloon to cross the lesion. Transthoracic echocardiography showed decreased LV systolic function (39%) with interior-septal regional …

Non-Cardiac Surgery After Percutaneous Coronary Intervention

Perioperative management of patients after percutaneous coronary intervention presents physicians with unique challenges and dilemmas. Although newer generation drug-eluting stents, transcatheter-based therapies, and minimally invasive surgical techniques have changed the medical landscape, guidelines for managing perioperative patients after percutaneous intervention are based largely on expert opinion and inconsistent data from an earlier era. In conclusion, the aims of this review are to summarize the data pertinent to managing patients after percutaneous coronary intervention in the perioperative period and to explore future perspectives.

Differential cardiovascular profiles of sodium-glucose cotransporter 2 inhibitors: critical evaluation of empagliflozin

One of the most feared repercussions of type 2 diabetes mellitus is the risk of adverse cardiovascular outcomes. The current antidiabetic agents on the market have had difficulty in showing cardiovascular outcome improvement. The EMPA-REG OUTCOME trial studied the sodium-glucose cotransporter 2 inhibitor empagliflozin in type 2 diabetic patients at high risk of cardiovascular events. The trial results revealed a decrease in the composite primary end points of death from cardiovascular causes, nonfatal myocardial infarction, and nonfatal stroke in those taking empagliflozin vs placebo. Those taking the medication also had a significant decrease in death from any cause, death from cardiovascular cause, and hospitalization for heart failure. The EMPA-REG trial is paradigm shifting because it demonstrates a clear mortality benefit to cardiovascular outcomes with a low side-effect profile, in contrast to prior outcome studies of hypoglycemic agents. Further studies are required to better clarify the long-term safety and efficacy of this promising class of diabetic drugs.