Left Ventricular Ejection Time Derived From the Common Carotid Artery Doppler Waveform: Association With Left Ventricular Ejection Fraction and Prediction of Heart Failure.

OBJECTIVES: Left ventricular ejection time (LVET) is measured from blood pressure tracings as the interval from end diastole to the dicrotic notch and shows associations with left ventricular ejection fraction (LVEF) and heart failure. LVET can be measured on common carotid artery Doppler waveforms. We therefore studied the possible associations of common carotid artery LVET with LVEF measured by echocardiography and heart failure. METHODS: We performed a retrospective study of 110 patients who had transthoracic echocardiography and carotid Doppler evaluations within 1 day of each other. LVEF was determined by the biplane modified Simpson method. LVET was measured from left common carotid artery Doppler tracings. Linear regression was used to evaluate associations between LVET and LVEF. We also used logistic regression with LVEF of less than 40% as a cut point for heart failure to generate a receiver operating characteristic curve, estimate the area under the curve, and calculate sensitivity and specificity. RESULTS: LVET was associated with LVEF (P < .0001). The area under the curve of LVET for heart failure was 0.81 (95% confidence interval [CI], 0.72-0.87), and the sensitivity and specificity were 76.9% (95% CI, 65.4%-88.4%) and 65.5% (95% CI, 53.4%-77.8%), respectively, for LVET of 321 milliseconds. CONCLUSIONS: LVET measured on common carotid artery Doppler tracings decreases with LVEF and is strongly associated with prevalent heart failure. Based on what is known of blood pressure-measured LVET, common carotid artery Doppler waveform-derived LVET could be used to serially monitor cardiac function.

Outcomes of infrainguinal bypass determined by age in the Vascular Study Group of New England.

BACKGROUND: Many believe extremes of age correlate with poorer outcomes in treatment for lower extremity peripheral arterial disease (PAD). We hypothesized that the youngest patients would have significantly poorer outcomes compared with older cohorts due to the precocious nature of their PAD. METHODS: We studied all patients in the Vascular Study Group of New England database undergoing infrainguinal bypass for PAD between 2003 and 2013. Age was grouped by <50 years, 50 to 79 years, and ≥80 years. Our primary outcomes were 1-year freedom from a major adverse limb event (MALE), defined as ipsilateral amputation or need for secondary intervention, and amputation-free survival. A second analysis was performed to analyze the subgroup of patients aged <50 years with critical limb ischemia (CLI), which included a Cox regression model to determine risk factors for MALE or death at 1 year. RESULTS: Of 5265 patients who were treated with infrainguinal bypass for PAD, 324 (6.2%) were aged <50 years. The mean age was 44.6 years, and 66.4% were male. The proportion of African Americans was significantly higher in the youngest age group (<50 years: 6.8% vs 50-79 years: 3.5%, P = .002; vs ≥80 years: 3.5%, P = .013). More bypasses were done for claudication than acute limb ischemia in patients aged <50 years (33.3% vs 11.4%). More vein grafts were used vs prosthetic (<50 years: 72.1% vs 50-79 years: 65.9%, P = .024; vs ≥80 years: 62.6%, P = .002). Fewer concomitant proximal procedures were performed compared with the older groups (<50 years: 37.7% vs 50-79 years: 51.1%, P < .001; vs ≥80 years: 39.5%, P = .045). More young patients returned to the operating room within their initial hospitalization for early graft thrombosis (<50 years: 5.6% vs 50-79 years: 2.9%, P = .001; vs ≥80 years: 2.4%, P = .009) and revision (<50 years: 4.7% vs 50-79 years: 2.2%, P = .012; vs ≥80 years: 1.4%, P = .002) compared with the older patients. Overall, MALE-free survival was similar across age groups (P = .323), as were patency and amputation rates. When considering only patients with CLI, MALE-free survival in the youngest patients was again similar (P = .171) but with significantly more major amputations at 1 year (P = .022). CONCLUSIONS: For patients aged <50 undergoing infrainguinal bypass surgery, this large series demonstrates similar overall medium-term graft-related outcomes compared with older cohorts. Further, although the youngest patients with CLI have similar MALEs, their amputation rates are higher than in older cohorts.

Association of common carotid artery Doppler-determined dicrotic notch velocity with the left ventricular ejection fraction.

OBJECTIVES: The appearance of the dicrotic notch on blood pressure tracings is associated with impaired cardiac function. Common carotid artery waveforms have similar fiduciary markers, yet they have not been related to cardiac function. We studied associations of common carotid artery dicrotic notch velocities with the left ventricular ejection fraction (LVEF) determined by echocardiography. METHODS: We conducted a retrospective study of 37 patients who had cardiac echocardiography and carotid Doppler evaluations within 1 day of each other. The LVEF was determined by the biplane modified Simpson rule. Doppler parameters were measured from tracings of the left common carotid artery 4 cm from the flow divider. Linear regression and stepwise multivariable linear regression models were used to evaluate any association between the LVEF and the following variables: age, sex, peak systolic velocity (PSV), end-diastolic velocity (EDV), dicrotic notch velocity, rise time (EDV to PSV), resistive index, and cardiac cycle length. RESULTS: The dicrotic notch velocity was the only variable associated with the LVEF (P = .028) in a bivariate analyses. A backward selection stepwise multivariable equation predicting the LVEF had the dicrotic notch (P = .001) and resistive index (P = .01) as significant predictors, whereas the cardiac cycle length (P = .08) and PSV (P = .08) were borderline not significant. Model goodness of fit was R(2) = 0.37 (P = .004). CONCLUSIONS: Dicrotic notch velocities measured from common carotid artery Doppler waveforms are associated with the LVEF and might offer some clinical value in selected cases.

Value of complete full-length lower extremity sonography in patients undergoing computed tomographic pulmonary angiography.

OBJECTIVES: To evaluate the diagnostic yield of complete lower extremity venous sonography for diagnosing deep venous thrombosis (DVT) in patients undergoing computed tomographic (CT) pulmonary angiography for suspected pulmonary embolism (PE). METHODS: We retrospectively reviewed all cases of lower extremity venous sonography and CT pulmonary angiography performed within 1 day of each other (n = 147) in a tertiary care center. Indications for the studies performed, angiographic findings, sonographic findings, age, sex, inpatient/outpatient status, lower extremity symptoms, and treatment status were recorded. Prevalence rates and patient characteristics were compared by χ(2) and Fisher exact probability tests where appropriate. Multivariable logistic regression with acute PE as the outcome was performed for age, sex, interval between angiography and sonography, indication for angiography, inpatient/outpatient status, and venous sonographic findings. RESULTS: The prevalence of PE (23.8%) was similar to the prevalence of DVT (27.9%). Angiographic findings were not associated with the interval between angiography and sonography or inpatient/outpatient status. Acute DVT was more likely (P = .0009) when angiographic findings were positive (51.4%), but DVT prevalence was still substantial (20.5%) in patients with negative angiographic findings. Lower extremity symptoms were not associated with DVT in cases with negative angiographic findings (P = .48). Eighteen of the 23 patients with acute DVT and negative angiographic findings were treated. CONCLUSIONS: There is a high rate of DVT in a population undergoing CT pulmonary angiography for suspected PE even when PE is not diagnosed. Our data apply to a tertiary care institution, suggest a surveillance bias, and favor the utility of venous sonography in this population.

The utility of screening for deep venous thrombosis in asymptomatic, non-ambulatory neurosurgical patients.

OBJECTIVES: Decisions regarding deep venous thrombosis (DVT) prophylaxis are complicated in neurosurgical patients because of the potential for catastrophic bleeding complications. Screening with venous duplex ultrasound (VDUS) may improve outcomes, but can strain hospital resources. Since there is little data to guide VDUS surveillance, we investigated the utility of a comprehensive VDUS screening program in neurosurgical patients. METHODS: Medical records of patients admitted to the neurosurgical service at a university-affiliated hospital from October 2007 through January 2010 who underwent weekly VDUS of the lower extremities until ambulatory or discharged were retrospectively reviewed. Demographics, comorbidities, interventions, and use of DVT prophylaxis were recorded. All patients in this study were asymptomatic for clinical evidence of DVT. When DVT was identified, VDUS reported its location and progression. RESULTS: One hundred seventy-four consecutive patients were screened according to the established protocol. They had 312 VDUS studies, 68 (21.8%) of which were positive in 40 (23%) unique patients; 10 were bilateral and two catheter-related. There were no documented pulmonary emboli in this series. Seventeen patients (37.7%) had isolated calf DVT, four of which were bilateral (totaling 21 thrombi), and 9 (20%) had coexistent thrombi in calf and proximal veins. Of the 21 isolated calf DVTs, 15 had follow-up studies and two progressed to the popliteal or ileofemoral vein on follow-up (13.3%). Mechanical prophylaxis was uniformly utilized, but chemical prophylaxis varied based on surgeons' assessment of bleeding risk. DVT developed in 19.3% (28/145) of patients receiving prophylactic medication (unfractionated heparin or low-molecular weight heparin) and 41.4% (12/29) receiving no chemoprophylaxis (P < .001). The only patient characteristic that correlated with DVT risk was a body mass index <30 (9.1% vs 29.4%, P = .01). CONCLUSIONS: Despite the uniform application of mechanical DVT prophylaxis and the use of chemoprophylaxis in a majority of patients, we found a 23% incidence of DVT in these hospitalized, nonambulatory, neurosurgical patients. No patients with isolated calf DVT had an embolic complication but 13.3% progressed proximally in short-term follow-up. While chemical prophylaxis significantly reduced DVT risk, no factor was sufficiently predictive to exclude patients from screening. These data substantiate the importance of full leg VDUS screening and maximizing DVT prophylaxis in this high risk population.

Correlation of duplex ultrasound scanning-derived valve closure time and clinical classification in patients with small saphenous vein reflux: Is lesser saphenous vein truly lesser?

OBJECTIVE: We recently identified small saphenous vein (SSV) reflux as a significant risk factor for ulcer recurrence in patients with severe chronic venous insufficiency (CVI) undergoing perforator vein ligation. In this study we examined the role of SSV reflux in patients across the spectrum of CVI. METHODS: From March 15, 1997, to December 24, 2002, clinical and duplex ultrasound (US) scanning data from all valve closure time studies performed in our vascular laboratory were prospectively recorded. Valve closure time in the deep and superficial leg veins was assessed with the rapid cuff deflation technique; reflux time greater than 0.5 seconds was considered abnormal. SSV reflux was correlated with the CEAP classification system and eventual surgical procedure. Data were analyzed with Pearson chi(2) analysis. RESULTS: We analyzed 722 limbs in 422 patients, 265 (63%) female patients and 157 (37%) male patients, with a mean age of 48 +/- 12.8 years (range, 16-85 years). In the entire cohort the cause was congenital (Ec) in 5 patients, primary (Ep) in 606 patients, and secondary (Es) in 112 patients. SSV reflux was present in 206 limbs (28.5%) evaluated. Among limbs with SSV reflux, Ec = 4 (2%), Ep = 162 (79%), and Es = 40 (19%). SSV reflux did not correlate with gender, side, or age. The prevalence of SSV reflux increases with increasing severity of clinical class: C1-C3, 25.8% versus C4-C6, 36.1% (P =.006). SSV reflux is highly associated with deep venous reflux, 35.2% of femoral vein reflux (P =.015), 35.8% of femoral vein plus popliteal vein reflux (P =.001), and 40.5% of isolated popliteal vein reflux (P <.001). Great saphenous vein (GSV) reflux was identified in 483 (67%) limbs studied with valve closure time, whereas SSV reflux was present in 206 (28%) limbs. In this cohort, 127 GSV or SSV surgical procedures were performed subsequent to valve closure time examination. Among these operations 107 (84%) were GSV procedures, and only 20 (16%) were SSV procedures. CONCLUSION: SSV reflux is most common in patients demonstrating severe sequelae of CVI, such as lipodermatosclerosis or ulceration. The increasing prevalence of SSV reflux in more severe clinical classes and the strong association of SSV reflux and deep venous reflux suggest that SSV may have a significant role in CVI. Our data further show that, in our institution, a GSV with reflux is more than twice as likely to be surgically corrected as an SSV with reflux. It is time for the SSV to assume greater importance in the treatment of lower extremity venous disease. Future improvements in surgical techniques for access and visualization of the SSV may facilitate this method.