Gagan D. Singh

Smoking cessation is associated with decreased mortality and improved amputation-free survival among patients with symptomatic peripheral artery disease

OBJECTIVE Although smoking cessation is recommended for all patients with peripheral artery disease, there are little data regarding the prevalence of smoking among patients at the time of angiography or the effect of smoking cessation on clinical outcomes. METHODS Consecutive patients with claudication or critical limb ischemia who underwent peripheral angiography from 2006 to 2013 were included in an observational cohort analysis. Smoking status was assessed at the time of angiography and during follow-up clinic visits. Kaplan-Meier analysis was used to assess the relationship between smoking cessation, mortality, and amputation-free survival. RESULTS Among 739 patients (423 men and 316 women; mean age, 60 ± 12 years), 204 (28%) remained active smokers at the time of lower extremity angiography. At the time of angiography, the mean number of cigarettes smoked per day was 16 ± 10, and the mean pack-years was 40 ± 25. During the course of the subsequent year, 61 patients (30%) successfully quit smoking and maintained continued abstinence. Baseline medication use between groups did not differ significantly. The mean ankle-brachial index was also similar for quitters vs nonquitters (0.53 ± 24 vs 0.49 ± 0.22; P = .3). During follow-up to 5 years, patients who quit smoking had significantly lower all-cause mortality (14% vs 31%; hazard ratio, 0.40; 95% confidence interval, 0.18-0.90) and improved amputation-free survival (81% vs 60%; hazard ratio, 0.43, 95% confidence interval, 0.22-0.86) compared with patients who continued smoking, with most of the difference driven by reduced mortality among patients who quit smoking. The findings remained significant on multivariable analysis. CONCLUSIONS Approximately one-third of active smokers with peripheral artery disease successfully quit smoking ≤ 1 year after lower extremity angiography. Patients who quit smoking have lower mortality and improved amputation-free survival compared with patients who continue smoking.

The Epidemiology, Clinical Manifestations, and Management of Chagas Heart Disease

Chagas disease results from infection by the protozoan parasite Trypanosoma cruzi and is endemic in Latin America. T cruzi is most commonly transmitted through the feces of an infected triatomine, but can also be congenital, via contaminated blood transfusion or through direct oral contact. In the acute phase, the disease can cause cardiac derangements such as myocarditis, conduction system abnormalities, and/or pericarditis. If left untreated, the disease advances to the chronic phase. Up to one‐half of these patients will develop a cardiomyopathy, which can lead to cardiac failure and/or ventricular arrhythmias, both of which are major causes of mortality. Diagnosis is confirmed by serologic testing for specific immunoglobulin G antibodies. Initial treatment consists of the antiparasitic agents benznidazole and nifurtimox. The treatment of Chagas cardiac disease comprises standard medical therapy for heart failure and amiodarone for ventricular arrhythmias, with consideration for implantable cardioverter‐defibrillator. Chagas disease causes the highest infectious burden of any parasitic disease in the Western Hemisphere, and increased awareness of this disease is essential to improve diagnosis, enhance management, and reduce spread.

Nitinol Self-Expanding Stents vs. Balloon Angioplasty for Very Long Femoropopliteal Lesions

Purpose To compare the patency rates and clinical outcomes of balloon angioplasty vs. nitinol stent placement for patients with short (≤150 mm) as compared to long (>150 mm) femoropopliteal (FP) occlusive lesions. Methods Between 2006 and 2011, 254 patients (134 men; mean age 68 years) underwent FP angioplasty. The majority of patients (64%) were treated for critical limb ischemia. One hundred thirty-nine (55%) patients had short FP lesions ≤150 mm, while 115 patients had long FP lesions >150 mm. The mean lesion length was 78±43 mm in the short FP lesion group and 254±58 mm in the long FP lesion group. Duplex ultrasound follow-up with a peak systolic velocity ratio ≥2.0 was used to define restenosis. Results The overall procedure success rate was 98%. One hundred forty-eight (58%) patients underwent stent placement. The mean number of stents deployed for treatment of short FP lesions was 1.0±0.4 vs. 2.0±0.7 for long FP lesions (p<0.001). The primary patency rate of short FP lesions treated with balloon angioplasty vs. stenting was 66% vs. 63% at 1 year (p=0.7). For long FP lesions, the 1-year primary patency rates of balloon angioplasty vs. stenting were 34% vs. 49% (p=0.006). Balloon angioplasty of long FP lesions was also associated with significantly lower assisted primary and secondary patency compared to stenting (p<0.05 for all comparisons). Sustained clinical improvement was >90% at 30 days but declined to 62% to 75% at 1 year. Conclusion Balloon angioplasty and stent placement result in similar patency rates and clinical outcomes for shorter to medium-length FP lesions. In comparison, stent placement in long FP lesions is associated with superior outcomes to balloon angioplasty, even when multiple stents are required. Procedure success and clinical improvement can be achieved in the majority of patients, but rates of restenosis remain high.

Association of dual-antiplatelet therapy with reduced major adverse cardiovascular events in patients with symptomatic peripheral arterial disease

OBJECTIVE This study was conducted to determine whether there is additive benefit of dual-antiplatelet therapy (DAPT) with aspirin (acetylsalicylic acid [ASA]) and clopidogrel compared with ASA monotherapy among patients with symptomatic peripheral arterial disease. METHODS This was an observational cohort analysis that included 629 patients with claudication or critical limb ischemia. The prevalence of patients taking ASA monotherapy vs DAPT was assessed monthly for up to 3 years. A propensity model was constructed to adjust for baseline demographic characteristics and to assess the effect of DAPT on major adverse cardiovascular events (MACEs) and major adverse limb events. RESULTS At baseline, 348 patients were taking DAPT and 281 were taking ASA monotherapy. During 3 years of follow-up, 50 events (20%) occurred in the DAPT group vs 59 (29%) in the ASA monotherapy group. After propensity weighting, DAPT use was associated with a decreased risk of MACEs (adjusted hazard ratio [HR], 0.65; 95% confidence interval [CI], 0.44-0.96) and overall mortality (adjusted HR, 0.55; 95% CI, 0.35-0.89). No association was found between DAPT use and the risk of major amputation (adjusted HR, 0.69; 95% CI, 0.37-1.29). In a subgroup of 94 patients who underwent point-of-care platelet function testing, 21% had decreased response to ASA and 55% had a decreased response to clopidogrel. No association was found between a reduced response to ASA or clopidogrel and adverse events at 1 year. CONCLUSIONS DAPT may be associated with reduced rates of MACEs and death among patients with symptomatic peripheral arterial disease.

Endovascular recanalization of infrapopliteal occlusions in patients with critical limb ischemia

BACKGROUND Endovascular therapies are increasingly used for treatment of critical limb ischemia (CLI). Infrapopliteal (IP) occlusions are common in CLI, and successful limb salvage may require restoration of arterial flow in the distribution of a chronically occluded vessel. We sought to describe the procedural characteristics and outcomes of patients with IP occlusions who underwent endovascular intervention for treatment of CLI. METHODS All patients with IP interventions for treatment of CLI from 2006 to 2012 were included. Angiographic and procedural data were compared between patients who underwent intervention for IP occlusions vs IP stenosis. Restenosis was determined by Doppler ultrasound imaging. Limb salvage was the primary end point of the study. Additional end points included primary patency, primary assisted patency, secondary patency, occlusion crossing success, procedural success, and amputation-free survival. RESULTS A total of 187 patients with CLI underwent interventions for 356 IP lesions, and 77 patients (41%) had interventions for an IP occlusion. Patients with an intervention for IP occlusion were more likely to have zero to one vessel runoff (83% vs 56%; P < .001) compared with interventions for stenosis. Compared with IP stenoses, IP occlusions were longer (118 ± 86 vs 73 ± 67 mm; P < .001) and had a smaller vessel diameter (2.5 ± 0.8 vs 2.7 ± 0.5 mm; P = .02). Wire crossing was achieved in 83% of IP occlusions, and the overall procedural success for IP occlusions was 79%. The overall 1-year limb salvage rate was 84%. Limb salvage was highest in the stenosis group, slightly lower in the successful occlusion group, and lowest in the failed occlusion group (92% vs 75% vs 58%, respectively; P = .02). Unsuccessfully treated IP occlusions were associated with a significantly higher likelihood of major amputation (hazard ratio, 5.79; 95% confidence interval, 1.89-17.7) and major amputation or death (hazard ratio, 2.69; 95% confidence interval, 1.09-6.63). CONCLUSIONS Successful endovascular recanalization of IP occlusions can be achieved with guidewire and support catheter techniques in most patients. In patients selected for an endovascular-first approach for IP occlusions in CLI, this strategy can be successfully implemented with favorable rates of limb salvage.

Association of elevated fasting glucose with lower patency and increased major adverse limb events among patients with diabetes undergoing infrapopliteal balloon angioplasty.

Diabetes mellitus (DM) is a significant risk factor for loss of patency after endovascular intervention, but the contribution of glycemic control to infrapopliteal artery patency among patients with DM is unknown. All percutaneous infrapopliteal interventions among patients with DM from 2006 to 2013 were reviewed and pre-procedure fasting blood glucose (FBG) was recorded. The primary endpoint was primary patency at 1 year as determined by duplex ultrasound. A total of 309 infrapopliteal lesions in 149 patients with DM were treated with balloon angioplasty during the study period. The median FBG was 144 mg/dL. At 1 year, the rate of primary patency was 16% for patients with FBG above the median, compared to 46% for patients with FBG below the median (hazard ratio (HR) 1.82 for FBG ≥144, p=0.005). Amputation rates at 1 year trended higher among patients with high versus low FBG (24% vs 15%, p=0.1). One year major adverse limb event rates were also higher for patients with high versus low FBG (35% vs 23%, p=0.05). Although patients with high FBG were more likely to have insulin-requiring DM (73% vs 50%, p=0.003) the association of high FBG with loss of primary patency remained significant even after adjusting for insulin use as well as other lesion-specific characteristics (adjusted HR 1.8, 95% CI 1.2–2.8). In conclusion, high fasting blood glucose at the time of infrapopliteal balloon angioplasty is associated with significantly decreased primary patency and may also be a risk factor for major adverse limb events among patients with a threatened limb.

Transradial and transfemoral coronary angiography and interventions: 1-Year outcomes after initiating the transradial approach in a cardiology training program

BACKGROUND Limited data are available regarding the safety and feasibility of initiating transradial (TR) diagnostic coronary angiography (CA) and percutaneous coronary intervention (PCI) in cardiology fellowship programs. METHODS From July 2010 to June 2011, University of California, Davis Medical Center, adopted the TR approach with supervised cardiology fellows as the primary operators. Procedural variables and clinical outcomes of TR and transfemoral (TF) procedures were compared. To minimize confounding variables, ST-elevation myocardial infarction, bypass graft interventions, chronic total occlusions, and procedures with concomitant right heart catheterizations were excluded. To reflect the learning curve of the TR approach, this experience was assessed in 2 sequential 6-month periods. RESULTS A total of 402 diagnostic CAs and 255 PCIs were included. Transradial access was used in 141 (35%) of the CAs and in 72 (28%) of PCIs. Within the TR-CA and TF-CA (n = 261) groups, there was no difference between fluoroscopy (10.4 ± 6.0 vs 11.0 ± 8.9, P = .63) or procedure (31.8 ± 11.5 vs 33.2 ± 13.8, P = .55) time throughout the academic year with a significant trend toward lower contrast use (128 ± 52 vs 110 vs 50, P = .04) by the second half. In addition, during the second half of the academic year, the TR-CA showed significantly higher fluoroscopy (11.0 ± 8.9 vs 6.7 ± 6.8, P = .001) and procedure (33.2 ± 13.8 vs 27.2 ± 11.6, P = .0015) times when compared with TF-CA. Transfemoral PCI (n = 183) and TR-PCI showed no significant difference between all fluoroscopy and procedure time and contrast use when comparing the 2 halves of the academic year. When comparing TF with TR within each academic half year, there was no difference within the PCI group. Vascular complications were less with the TR approach. Overall procedural success rates were high, and there were low rates of crossover and periprocedural complications in both the TR and the TF groups. CONCLUSION A TR approach is safe for CA and PCI when performed by supervised operators in training. Although the learning curve for trainees appears slower for TR-CA compared with TF-CA, cardiology fellowship training programs should be encouraged to adopt TR procedures as part of their curriculum.

Coronary artery endothelial cells and microparticles increase expression of VCAM-1 in myocardial infarction

Coronary artery disease (CAD) is characterised by progressive atherosclerotic plaque leading to flow-limiting stenosis, while myocardial infarction (MI) occurs due to plaque rupture or erosion with abrupt coronary artery occlusion. Multiple inflammatory pathways influence plaque stability, but direct assessment of endothelial inflammation at the site of coronary artery stenosis has largely been limited to pathology samples or animal models of atherosclerosis. We describe a technique for isolating and characterising endothelial cells (ECs) and EC microparticles (EMPs) derived directly from the site of coronary artery plaque during balloon angioplasty and percutaneous coronary intervention. Coronary artery endothelial cells (CAECs) were identified using imaging flow cytometry (IFC), and individual CAEC and EMP expression of the pro-atherogenic adhesion molecule vascular cell adhesion molecule-1 (VCAM-1) was assessed immediately following angioplasty. Patients with MI registered 73 % higher VCAM-1 expression on their CAECs and 79 % higher expression on EMPs compared to patients with stable CAD. In contrast, VCAM-1 expression was absent on ECs in the peripheral circulation from these same subjects. VCAM-1 density was significantly higher on CAECs and EMPs among patients with MI and positively correlated with markers of myocardial infarct size. We conclude that increased VCAM-1 expression on EC and formation of EMP at the site of coronary plaque is positively correlated with the extent of vascular inflammation in patients with myocardial infarction.

Angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use is associated with reduced major adverse cardiovascular events among patients with critical limb ischemia

Angiotensin converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) are recommended for secondary prevention in peripheral artery disease, but their effectiveness in patients with critical limb ischemia (CLI) is uncertain. We reviewed 464 patients with CLI who underwent diagnostic angiography or endovascular intervention from 2006–2013 at a multidisciplinary vascular center. ACEI or ARB use was assessed at the time of angiography. Major adverse cardiovascular events (MACE), mortality, and major adverse limb events (MALE) were assessed during three-year follow-up. Propensity weighting was used to adjust for baseline differences between patients taking and not taking ACEIs or ARBs. ACEIs or ARBs were prescribed to 269 (58%) patients. Patients prescribed ACEIs or ARBs had more baseline comorbidities including diabetes and hypertension (p<0.05). Patients prescribed ACEIs or ARBs had lower three-year unadjusted rates of MACE (40% versus 47%) and mortality (33% versus 43%). After propensity weighting, ACEI or ARB use was associated with significantly lower rates of MACE (hazard ratio [HR] 0.76, 95% confidence interval [CI] 0.58–0.99, p=0.04) and overall mortality (HR 0.71, 95% CI 0.53–0.95, p=0.02). There was no significant association between ACEI or ARB use and MALE (HR 0.97, 95% CI 0.69–1.35, p=0.2) or major amputation (HR 0.74, 95% CI 0.47–1.18, p=0.1). ACEI/ARB use is associated with lower MACE and mortality in patients with CLI, but there was no effect on limb-related outcomes.

Adherence to guideline-recommended therapies among patients with diverse manifestations of vascular disease

Background Current guidelines recommend aspirin, statins, angiotensin-converting enzyme inhibitors (ACEIs), and smoking abstinence for all patients with vascular disease. There is little data on the variation in adherence to guideline-recommended therapies among patients with different clinical manifestations of vascular disease. Purpose To analyze the variation in adherence to guideline-recommended therapies among patients with diverse manifestations of vascular disease. Methods We analyzed a comprehensive database of all patients with critical limb ischemia, claudication, acute limb ischemia, carotid artery stenosis, subclavian artery stenosis, renal artery stenosis, or mesenteric ischemia who underwent angiography between 2006 and 2013 at a multidisciplinary vascular center. Results Among 1,114 patients with vascular disease, adherence to guideline-recommended therapy at time of angiography included use of aspirin in 936 (84%), statins in 753 (68%), ACEIs in 673 (60%), and smoking abstinence in 788 (71%). A total of 335 (30%) patients utilized all four guideline-recommended therapies. Adherence to four guideline-recommended therapies was lowest among patients with acute limb ischemia (14%) and highest among patients with renal artery stenosis (37%). Among all patients with vascular disease, the range of adherence to individual guidelines was 64%–91% for aspirin, 43%–83% for statins, 49%–66% for ACEIs, and 47%–78% for smoking abstention. Conclusion The majority of patients with diverse manifestations of vascular disease take aspirin and abstain from smoking while fewer patients are prescribed ACEIs and statins. Among the current recommendations, statins have the widest variation in adherence. Less than one-third of patients with diverse manifestations of vascular disease are prescribed all four guideline-recommended therapies.