Sridhar Venkatachalam

The nutcracker syndrome

Left renal vein (LRV) compression, commonly referred to as the nutcracker syndrome or renal vein entrapment syndrome, is a rare and often overlooked condition. Anatomically, the LRV traverses the space between the superior mesenteric artery and the aorta in close proximity to the origin of the artery. In affected individuals, the LRV is subjected to compression between these two structures, resulting in renal venous hypertension. A review of published data on this condition reveals either case reports or small case series. The classic symptoms of nutcracker syndrome include left flank pain with gross or microscopic hematuria. Patients are often children or young adults, with a slight predisposition for women who may also present with pelvic congestion symptoms such as pelvic pain and dyspareunia. Most patients have disease symptoms for many years and nondiagnostic investigations before proper diagnosis can be made. Appropriate diagnostic work-up and treatment may help alleviate patient morbidity from this chronic condition. Although surgical repair has been the standard of care, more recently endovascular intervention has become the first line of therapy. This tabular review compiles published cases in the adult population during the period between 1980 and 2009.

A Direct Comparison of Early and Late Outcomes With Three Approaches to Carotid Revascularization and Open Heart Surgery

OBJECTIVES The aim of this study was a comparison of risk-adjusted outcomes of 3 approaches to carotid revascularization in the open heart surgery (OHS) population. BACKGROUND Without randomized clinical trials, the best approach to managing coexisting severe carotid and coronary disease remains uncertain. Staged carotid endarterectomy (CEA) followed by OHS or combined CEA and OHS are commonly used. A recent alternative is carotid artery stenting (CAS). METHODS From 1997 to 2009, 350 patients underwent carotid revascularization within 90 days before OHS at a tertiary center: 45 staged CEA-OHS, 195 combined CEA-OHS, and 110 staged CAS-OHS. The primary composite endpoint was all-cause death, stroke, and myocardial infarction (MI). Staged CAS-OHS patients had higher prevalence of previous stroke (p = 0.03) and underwent more complex OHS. Therefore, the propensity score adjusted multiphase hazard function models with modulated renewal to account for staging, and competing risks were used. RESULTS Using propensity analysis, staged CAS-OHS and combined CEA-OHS had similar early hazard phase composite outcomes, whereas staged CEA-OHS incurred the highest risk driven by interstage MI. Subsequently, staged CAS-OHS patients experienced significantly fewer late hazard phase events compared with both staged CEA-OHS (adjusted hazard ratio: 0.33; 95% confidence interval: 0.15 to 0.77; p = 0.01) and combined CEA-OHS (adjusted hazard ratio: 0.35; 95% confidence interval: 0.18 to 0.70; p = 0.003). CONCLUSIONS Staged CAS-OHS and combined CEA-OHS are associated with a similar risk of death, stroke, or MI in the short term, with both being better than staged CEA-OHS. However, the outcomes significantly favor staged CAS-OHS after the first year.

Contemporary management of concomitant carotid and coronary artery disease

The best approach to the management of concomitant severe carotid and coronary artery disease remains unanswered. The American College of Cardiology/American Heart Association (ACC/AHA) guidelines recommend carotid endarterectomy (CEA) in asymptomatic carotid stenosis of ≥80% either prior to or combined with coronary artery bypass surgery (CABG). Currently, there is no consensus as to which surgical approach is superior. More recently, carotid artery stenting (CAS) prior to CABG is emerging as an alternative option with promising results in asymptomatic patients considered ‘high risk’ for CEA. A <3% composite event rate has been set as a benchmark for isolated CAS or CEA in asymptomatic patients by the ACC/AHA; however, most CEA or CAS studies in patients requiring concomitant CABG have shown event rates ranging from 10–12%. This review examines the available data on carotid revascularisation in relation to CABG surgery to aid in the risk–benefit decision analysis in this controversial area.

Management of carotid disease in patients undergoing coronary artery bypass surgery: is it time to change our approach?

Purpose of review The management of concurrent severe carotid and coronary disease is a subject of ongoing debate in the absence of randomized clinical trials. Amidst the growing controversy, the clinician has to carefully tailor the best strategy for a given patient based on neurologic and cardiac symptoms. This review aims to compile current evidence in this area to help plan strategies for the optimal management of coexisting severe carotid and coronary disease. Recent findings Carotid revascularization with carotid endarterectomy (CEA) or stenting (CAS) is frequently performed in conjunction with coronary artery bypass surgery (CABG) in the United States for asymptomatic carotid disease. The risk of perioperative stroke with unilateral asymptomatic 70–99% carotid stenosis is likely small based on several observational data. Moreover, the risk associated with both staged and combined CEA-CABG procedures in the asymptomatic population may outweigh any benefit. Carotid artery stenting is an alternative option in patients with severe coronary disease who are considered ‘high risk’ for CEA. Neurologically symptomatic patients require carotid revascularization prior to or in conjunction with CABG surgery. Ultimately, the choice of carotid revascularization or conservative management will depend on clinical characteristics, anatomy, and local expertise. Summary Severe carotid disease in the CABG population is often unilateral and asymptomatic. Based on the available data, conservative carotid therapy in the low-risk asymptomatic individuals is likely the best treatment option. Carotid revascularization may be justified in symptomatic or high-risk patients such as those with contralateral carotid occlusion or bilateral severe stenosis.

Combined antegrade-retrograde intervention to improve chronic total occlusion recanalization in high-risk critical limb ischemia.

BACKGROUND When conventional antegrade attempts (antegrade approach) to cross chronic total occlusion (CTO) lesions in critical limb ischemia (CLI) fail, and if surgical revascularization is not possible, limb outcomes may be expected to be poor. In this high-risk cohort, we sought to examine whether combined antegrade-retrograde intervention with the simultaneous use of a distal retrograde access (combined approach) improves recanalization success. METHODS From September 2011 to 2012, infrainguinal endovascular interventions were first attempted using antegrade approach in 27 consecutive patients (28 limbs) with CLI and infrainguinal CTO. All patients were poor surgical candidates. In the 11 limbs where antegrade approach failed, the combined approach was attempted. The primary end point was successful CTO lesion crossing. The secondary end points were technical success with ≤30% diameter residual stenosis of the target lesion, major amputation (transtibial or above), wound healing, target lesion revascularization (TLR), and access site complications that include hematoma requiring exploration or transfusion, arteriovenous fistula, or pseudoaneurysm. RESULTS Of the 11 limbs that underwent combined approach, the primary end point was achieved in 9 limbs (82%). More notably, among the 28 limbs overall, CTO lesion crossing improved from 61% (95% confidence interval [CI]: 0.41-0.78) using antegrade approach alone to 93% (95% CI: 0.75-0.99) when supplemented by the combined approach. Similarly, the secondary end point of technical success improved from 50% (95% CI: 0.31-0.69) to 79% (95% CI: 0.59-0.91), respectively. Major amputation, wound healing (inclusive of postamputation status), and TLR rates were 9%, 100%, and 18%, respectively, during a median follow-up of approximately 4 months. No major procedural complications occurred with the combined approach. CONCLUSION Among CLI patients who are poor surgical candidates, the combined approach is a viable, safe, and effective strategy to improve overall success with endovascular therapies.

Basic Data Related to Endovascular Management of Peripheral Arterial Disease in Critical Limb Ischemia

Chronic critical limb ischemia occurs in the setting of severe peripheral arterial disease that is often characterized by advanced atherosclerosis at multiple levels in the lower extremity. Despite the challenges posed by the complexity of arterial disease in such patients, endovascular intervention is a less invasive alternative to infrainguinal bypass graft surgery in most patients, with low procedural morbidity and mortality. Continual advances in percutaneous techniques have made it possible to revascularize lesions considered nonamenable for endovascular intervention. For example, the development of dedicated peripheral wires, balloons, stents, and catheters allows the recanalization and revascularization of almost any anatomy. Pharmaceutical advances in risk factor modification for recurrent stenosis impact results. Such evolution makes data comparison difficult. This review aims to present the available data on endovascular therapy in critical limb ischemia patients reported over the past 2 decades.

Asymptomatic carotid stenosis: immediate revascularization or watchful waiting?

Based on several randomized clinical trials, carotid revascularization has been shown to reduce future stroke risk among individuals with severe asymptomatic carotid stenosis. However, a well-recognized problem with such prophylactic intervention is the risk of periprocedural stroke, death, or myocardial infarction. If actual stroke risk with asymptomatic carotid stenosis can be reduced significantly by aggressive medical management, carotid revascularization may yield marginal benefit or even cause harm especially in those with limited life expectancy. Based on recent observational data, it is becoming apparent that the stroke risk in this population has been declining with better medical management alone. This has prompted a few to avoid carotid revascularization for asymptomatic carotid stenosis altogether. Others feel such conclusions cannot be made with observational data alone. In the midst of this controversy, it is important that clinicians perform carotid revascularization on a case by case basis while ensuring optimal medical management in all patients. An algorithmic approach to decision making based on available evidence will enable clinicians to personalize patient management with efficiency.