Madhan Shanmugasundaram

The Relationship between Warfarin, Aspirin, and Clopidogrel Continuation in the Peri-procedural Period and the Incidence of Hematoma Formation after Device Implantation

Background: Many patients requiring permanent pacemaker (PPM) or implantable cardiac defibrillator (ICD) placement are anticoagulated with warfarin, aspirin (ASA), and clopidogrel for a number of thromboembolic risk indications. The present review sought to evaluate the relationship between continuation of these medications in the peri‐procedural period and the incidence of hematoma formation after implantation.

Peripheral Arterial Disease—What Do We Need to Know?

Peripheral artery disease (PAD) results from progressive narrowing of arteries secondary to atherosclerosis and is defined as an Ankle Brachial Index of <0.9. PAD is highly prevalent and is an increasing burden on both the economy and the patient, especially given the rapid shift in demographics in the United States. Despite its prevalence and association with cardiovascular disease, PAD is still underdiagnosed and undertreated. This may, in part, be related to lack of recognition from the physicians side or paucity of evidence from clinical trials. It has been shown that medical therapy approved for cardiovascular disease is effective in the treatment of PAD and decreases cardiovascular events. Various revascularization strategies are also available for improving symptoms and quality of life in these patients, yet they are underutilized. In an attempt to increase its recognition, PAD has been considered a coronary artery disease equivalent. This article reviews the diagnosis and management of PAD.

Dyslipidemia in the Elderly: Should it Be Treated?

Elderly or older adults constitute a rapidly growing segment of the United States population, thus resulting in an increase in morbidity and mortality related to cardiovascular disease—an increase that is reaching epidemic proportions. Dyslipidemia is a well established risk factor for cardiovascular disease and is estimated to account for more than half of the global cases of coronary artery disease. Despite the increased prevalence of dyslipidemia in the older adult population, controversy persists regarding the benefits of treatment in this group. Epidemiologic studies have shown that dyslipidemia is often underdiagnosed and under treated in this population probably as a result of a paucity of evidence regarding the impact of treatment in delaying the progression of atherosclerotic disease, concerns involving increased likelihood of adverse events or drug interactions, or doubts regarding the cost effectiveness of lipid‐lowering therapy in older adults. In conclusion, despite the proven efficacy of lipid‐lowering therapy in decreasing cardiovascular morbidity and mortality, these therapies have been underutilized in older patients. Copyright

Predictors of resuscitation outcome in a swine model of VF cardiac arrest: A comparison of VF duration, presence of acute myocardial infarction and VF waveform

INTRODUCTION Factors that affect resuscitation to a perfusing rhythm (ROSC) following ventricular fibrillation (VF) include untreated VF duration, acute myocardial infarction (AMI), and possibly factors reflected in the VF waveform. We hypothesized that resuscitation of VF to ROSC within 3min is predicted by the VF waveform, independent of untreated VF duration or presence of acute MI. METHODS AMI was induced by the occlusion of the left anterior descending coronary artery. VF was induced in normal (N=30) and AMI swine (N=30). Animals were resuscitated after untreated VF of brief (2min) or prolonged (8min) duration. VF waveform was analyzed before the first shock to compute the amplitude-spectral area (AMSA) and slope. RESULTS Unadjusted predictors of ROSC within 3min included untreated VF duration (8min vs 2min; OR 0.11, 95%CI 0.02-0.54), AMI (AMI vs normal; OR 0.11, 95%CI 0.02-0.54), AMSA (highest to lowest tertile; OR 15.5, 95%CI 1.7-140), and slope (highest to lowest tertile; OR 12.7, 95%CI 1.4-114). On multivariate regression, untreated VF duration (P=0.011) and AMI (P=0.003) predicted ROSC within 3min. Among secondary outcome variables, favorable neurological status at 24h was only predicted by VF duration (OR 0.22, 95% CI 0.05-0.92). CONCLUSIONS In this swine model of VF, untreated VF duration and AMI were independent predictors of ROSC following VF cardiac arrest. AMSA and slope predicted ROSC when VF duration or the presence of AMI were unknown. Importantly, the initial treatment of choice for short duration VF is defibrillation regardless of VF waveform.

Analysis of amplitude spectral area and slope to predict defibrillation in out of hospital cardiac arrest due to ventricular fibrillation (VF) according to VF type: Recurrent versus shock-resistant☆

BACKGROUND In out-of-hospital cardiac arrest (OHCA) due to ventricular fibrillation (VF), VF may recur during resuscitation (recurrent VF) or fail to defibrillate (shock-resistant VF). While retrospective studies have suggested that amplitude spectral area (AMSA) and slope predict defibrillation, it is unknown whether the predictive power is influenced by VF type. We hypothesized that in witnessed OHCA with initial rhythm of VF that the utility for AMSA and slope to predict defibrillation would differ between shock-resistant and recurrent VF. METHODS AMSA and slope were measured immediately prior to each shock. For second or later shocks, VF was classified as recurrent or shock-resistant. Cardiac arrest was classified according to whether the majority of shocks were for recurrent VF or shock-resistant VF. RESULTS 44 patients received 98 shocks for recurrent VF and 96 shocks for shock-resistant VF; 24 patients achieved ROSC in the field. AMSA and slope were higher in recurrent VF compared to shock-resistant VF (AMSA: 28.8±13.1 vs 15.2±8.6 mVHz, P<0.001, and slope: 2.9±1.4 vs 1.4±1.0 mVs(-1), P=0.001). Recurrent VF was more likely to defibrillate than shock-resistant VF (P<0.001). AMSA and slope predicted defibrillation in shock-resistant VF (P<0.001 for both AMSA and slope) but not in recurrent VF. Recurrent VF predominated in 79% of patients that achieved ROSC compared to 55% that did not (P=0.10). CONCLUSIONS In witnessed OHCA with VF as initial rhythm, recurrent VF is associated with higher values of AMSA and slope and is likely to re-defibrillate. However, when VF is shock-resistant, AMSA and slope are highly predictive of defibrillation.

Acute Coronary Syndrome in the Elderly

The spectrum of acute coronary syndrome (ACS) including unstable angina, non–ST‐elevation myocardial infarction and ST‐elevation myocardial infarction accounts for increasing numbers of deaths among persons age ≥ 65 years in the US. This is important given demographic changes involving falling birth rates and increasing life expectancy. Elderly patients are likely to benefit the most from treatment of ACS, even though community practice still demonstrates less use of cardial medications as an early‐invasive approach among this population. Copyright

Predictors of resuscitation in a swine model of ischemic and nonischemic ventricular fibrillation cardiac arrest: Superiority of amplitude spectral area and slope to predict a return of spontaneous circulation when resuscitation efforts are prolonged

Objective:We have demonstrated that a return of spontaneous circulation in the first 3 mins of resuscitation in swine is predicted by ventricular fibrillation waveform (amplitude spectral area or slope) when untreated ventricular fibrillation duration or presence of acute myocardial infarction is unknown. We hypothesized that in prolonged resuscitation efforts that return of spontaneous circulation immediately after a second or later shock with postshock chest compression is independently predicted by end-tidal CO2, coronary perfusion pressure, and ventricular fibrillation waveform measured before that shock in a swine model of ischemic and nonischemic ventricular fibrillation arrest. Design:Animal intervention study with comparison to a control group. Setting:University animal laboratory. Subjects:Twenty swine. Interventions:Myocardial infarction was induced by steel plug occlusion of the left anterior descending coronary artery. Ventricular fibrillation was untreated for 8 mins in normal swine (n = 10) and acute myocardial infarction swine (n = 10). Measurements and Main Results:End-tidal CO2, coronary perfusion pressure, and ventricular fibrillation waveform characteristics of amplitude spectral area and slope were analyzed before second or later shocks. For an amplitude spectral area >35 mV-Hz, the odds ratio for achieving return of spontaneous circulation after that shock was 72 (95% confidence interval, 3.8–1300; p = .004) compared with an amplitude spectral area <28 mV-Hz and with an area under the receiver operator characteristic curve of 0.86. For slope >3.6 mV/s, the odds ratio for achieving return of spontaneous circulation was 36 (95% confidence interval, 2.7–480; p = .007) compared with slope <2.72 mV/s with an area under the curve of 0.86. End-tidal CO2 and coronary perfusion pressure were not predictive of return of spontaneous circulation after a shock, although coronary perfusion pressure was significantly related to both amplitude spectral area (p < .001) and slope (p < .001). Conclusions:In prolonged untreated ventricular fibrillation arrest, the waveform characteristics of amplitude spectral area and slope predict the attainment of return of spontaneous circulation with a second or later shock. This has implications for the ideal means to customize the timing of shocks and chest compressions when return of spontaneous circulation is not promptly obtained.

Insertion of the Impella via the axillary artery for high-risk percutaneous coronary intervention

Hemodynamic support with the Impella device is an important tool during high risk percutaneous coronary intervention. This device is usually inserted via the femoral artery. However, some patients have severe peripheral artery disease precluding the use of the femoral artery for this purpose. The axillary artery is a viable alternative in these cases. We reviewed the two access techniques for inserting the Impella via the axillary artery and also described 6 cases of successful implantation.

Glycoprotein IIb/IIIa Antagonists

Patients with acute coronary syndrome and who undergo percutaneous coronary intervention are at a high risk for recurrent adverse cardiovascular events. There is a continuous search for an ideal antiplatelet medication that has a favorable risk benefit profile with a quick onset of peak action. Glycoprotein IIb/IIIa inhibitors (GP IIb/IIIa) were introduced with that precise idea in mind, that it is an intravenous antiplatelet agent with a rapid onset of action, which can be used to achieve maximal antiplatelet activity in patients with acute coronary syndrome (ACS) and those undergoing percutaneous coronary intervention (PCI). Abciximab, eptifibatide, and tirofiban are the three available intravenous GP IIb/IIIa inhibitors of which the latter two are small molecules. Initial trials that examined these agents were done in the balloon angioplasty era when P2Y12 receptor blocker use was not routine. These trials demonstrated a significant reduction in the composite end point of death, myocardial infarction (MI), and urgent target vessel revascularization predominantly driven by a reduction in recurrent MI that included periprocedural events. There is a definite increase in major and minor bleeding with these agents which needs to be weighed against the potential benefits before initiating the drug. More contemporary trials that were done on patients who were adequately treated with P2Y12 inhibitors failed to recreate the initial results, but nevertheless there was still a significant reduction in ischemic events. There is still a role for these agents in patients with high-risk non-ST segment elevation myocardial infarction and ST segment elevation myocardial infarction with heavy thrombus burden, particularly if they have not been adequately pretreated with P2Y12 inhibitors.

ACUTE LIMB ISCHEMIA IN A PREVIOUSLY UNDIAGNOSED CASE OF MID-VENTRICULAR NON-OBSTRUCTIVE HYPERTROPHIC CARDIOMYOPATHY

Mid-ventricular hypertrophic cardiomyopathy (HCM) is rare and when associated with an apical aneurysm has a high risk of thrombus formation and embolization. We report a case of a 70-year-old man with peripheral vascular disease who presented with acute progressive right leg pain. Peripheral angiography showed complete thrombotic occlusion of his right superficial femoral artery. Thrombolysis was successfully performed using alteplase. His post-procedure angiography which was obtained the next day showed complete revascularization with no residual stenosis. His echocardiogram showed an ill-defined mass in the left ventricular apex. The absence of residual atheroma on peripheral angiography suggested a primary embolic event. We obtained cardiac MRI which showed mid-ventricular HCM complicated by an apical aneurysm and small thrombus. Left ventricular apical aneurysm occurs commonly in mid-ventricular HCM and is associated with a worse prognosis. Cardiac magnetic resonance imaging (MRI) is superior to echocardiography in identifying left ventricular apical aneurysms and apical thrombi.