Huiting Chen

Predicting the learning curve and failures of total percutaneous endovascular aortic aneurysm repair

INTRODUCTION Percutaneous endovascular aneurysm repair (PEVAR) has been shown to be feasible; however, technical success is variable, reported to be between 46.2% and 100%. The objective of this study was to quantify the learning curve of the PEVAR closure technique and identify predictors of closure failure. METHODS We reviewed patient- and procedure-related characteristics in 99 consecutive patients who underwent PEVAR over a 30-month period in a single academic institution. A suture-mediated closure device (Proglide or Prostar XL) was used. Forward stepwise logistic regression was used to investigate associations between the failure of the closure technique and a number of patient and operative characteristics. To ensure objective assessment of the learning curve, a time-dependent covariate measuring time in calendar quarters was introduced in the model. Poisson regression was used to model the trend of observed failure events of the percutaneous technique over time. RESULTS Overall PEVAR technical success was 82%. Type of closure device (P<.35), patients body mass index (P<.86), type of anesthesia (P<.95), femoral artery diameter (P<.09), femoral artery calcification (P<.56), and sheath size as measured in Fr (P<.17) did not correlate with closure failure rates. There was a strong trend for a decreasing number of failure events over time (P<.007). The average decrease in the odds of technical failure was 24% per calendar quarter. The predicted probability of closure failure decreased from 45% per patient at the time of the initiation of our PEVAR program to 5% per patient at the end of the 30-month period. There were two postoperative access-related complications that required surgical repair. Need for surgical cutdown in the event of closure failure prolonged the operative time by a mean of 45 minutes (P<.001). No groin infections were seen in the percutaneous group or the failed group. CONCLUSIONS Technical failure can be reduced as the surgeon gains experience with the suture-mediated closure device utilized during PEVAR. Previous experience with the Proglide device does not seem to influence the learning curve.

Physiologic variations in venous and arterial hemodynamics in response to postural changes at the thoracic outlet in normal volunteers.

BACKGROUND Hemodynamic changes in vascular flow and waveforms measured across the thoracic outlet (TO) during positional changes may occur in normal individuals. The aim of this study was to establish the prevalence of significant arterial and venous hemodynamic variation in the limbs of normal volunteers during standardized upper extremity positional changes. METHODS Using Doppler ultrasound and photoplethysmography (PPG), we evaluated arterial and venous flow in 100 limbs of 50 normal volunteers in neutral position and in 5 different standardized arm positions, including 90° arm abduction (with head in neutral position, head turned ipsilaterally, and head turned contralaterally), arm extended above the head at 180°, and arm hyperextended at 200°. RESULTS There was great variability in the prevalence of abnormal venous and arterial flow changes depending on the arm position. Venous flow anomalies (loss of flow phasicity resulting in continuous, minimally continuous, or absent flow) were demonstrated in 60% of the limbs. The maneuver producing the greatest prevalence of venous flow abnormality was 90° arm abduction with contralateral head turn (34% of limbs), while arm hyperextension produced the least venous flow abnormalities (25% of limbs). In 13% of the limbs arterial flow abnormalities were found by PPG (absent tracings in 10% and dampened waveform in 5%), while 23% of the limbs showed increased arterial velocities (positional to neutral velocity ratio >2.0). The arm position producing the greatest prevalence of arterial flow anomaly was hyperextension (21% of limbs); while the arm positioning at 90° of abduction with the head in neutral position resulted in no arterial flow abnormalities. CONCLUSIONS The prevalence of upper extremity venous and arterial hemodynamic changes varies substantially in different arm positions. Our data suggest that physiologic anomalies in venous flow across the TO during postural changes are very common, while the absence of finger PPG arterial tracings occur in a very small percentage of the population. Abnormal venous flow across the TO with postural changes should be considered a highly prevalent finding in the normal population, and therefore carries little value in the diagnosis of TO syndrome. On the other hand, absence of arterial waveforms measured at the fingers by PPG testing during positional changes occurs in a small percentage of the normal population, and may represent abnormal compression at the TO in patients with upper extremity symptomatology.

Jaw claudication in the era of carotid stenting

Jaw claudication could result from external carotid artery (ECA) occlusive disease. Carotid artery stenting (CAS) has been shown to worsen the disease in the ECA. This could potentially worsen the symptoms in patients with pre-existing jaw claudication undergoing CAS. Meanwhile, ECA endarterectomy is routinely done during internal carotid artery endarterectomy (CEA). This has been shown to alleviate jaw claudication symptoms. We report a case of a high-risk patient for CEA who presented with symptomatic carotid disease as well as bilateral jaw claudication. Both symptoms resolved after CEA. We also present the case of another patient treated for recurrent high-grade carotid disease with CAS resulting in acute ECA occlusion and jaw claudication. High-risk patients with symptomatic carotid disease and jaw claudication should be considered for CEA and not only CAS.

Management of Chronic Venous Disease and Varicose Veins in the Elderly

Chronic venous insufficiency (CVI) affects millions of Americans, with impacted quality of life from pain, disability, and economic disablement. The prevalence of CVI increases with age, and with a growing elderly population, applying evidence-based treatment to this chronic condition becomes increasingly essential. The Society of Vascular Surgeons/American Venous Forum (SVS/AVF) guidelines provide recommendations and suggestions for many aspects of the history, physical exam, workup, and treatment of CVI to provide a consistent, evidence-based approach for physicians. In addition to these guidelines, the elderly population has special considerations specific to their needs. For example, the presence of multiple comorbidities or prescription medications may confound the physical exam, and the patients’ frail conditions may preclude their ability to lay flat or perform maneuvers for physiologic studies. Various anesthetic options must be weighed in this physiologically sensitive population. The risks and benefits of responses to surgical and medical therapies must also be considered. Varicose veins are an increasingly frequent cause of discomfort and decreased quality of life with age, and their surgical treatment has been shown to be more effective than conservative management alone to improving quality of life in both symptomatic and anatomic measures. From our experience, in an age 65 and older subset of total patients who underwent radiofrequency ablation (RFA) alone versus RFA + TIPP (transilluminated powered phlebectomy), there was a trend toward a higher percentage of patients who had RFA alone. In this elderly subset, Venous Clinical Severity Scores tended to improve more with RFA alone compared to RFA + TIPP, without a significant difference in complications between the two procedures.

Ruptured external jugular varix

Venous dilations of the jugular veins are uncommon and external jugular varix even rarer. We present the case of a 57-year-old woman with ruptured external jugular varix and the surgical repair of such. Surgical intervention is warranted in these rare venous malformations to prevent known complications of thromboembolism and rupture.

Pulmonary Embolism and SVC Syndrome

Pulmonary embolism (PE) is a potentially fatal condition caused by embolic occlusion of the pulmonary artery or one of its branches due to thrombotic material that has traveled through the bloodstream from elsewhere in the body. The majority of emboli are thrombi from the deep veins of the legs; less likely causes can be fat, air or amniotic fluid emboli. PE is a highly lethal condition that affects more than 600,000 patients annually in the United States and is responsible for 150,000 to 200,000 deaths every year.