Fewer Complications in the Obese Following Lower Extremity Endovascular Interventions

Obesity and Peripheral Artery Disease: Current Evidence and Controversies

PURPOSE OF REVIEW

Obesity is a significant public health problem and a major risk factor for the development and progression of atherosclerosis and its cardiovascular manifestations. Lower extremity peripheral artery disease (PAD) affects 3%-10% of the Western population and, if left untreated, can lead to devastating outcomes with both an increased risk of morbidity and mortality. Interestingly, the association between obesity and PAD remains debatable. Whereas it is well known that PAD and obesity frequently overlap in the same patients, many studies have demonstrated a negative association between obesity and PAD and a protective effect of obesity on disease development and progression, a phenomenon described as the "obesity paradox." Possible mechanisms for this paradox may include genetic background, as assessed by mendelian randomization studies, adipose tissue dysfunction, and body fat distribution rather than adiposity, while other factors, such as sex, ethnicity, sarcopenia in the elderly population, or aggressive treatment of co-existing metabolic conditions in individuals with obesity compared to those with normal weight, could have some impact as well.

RECENT RINDINGS

Few reviews and meta-analyses examining systematically the relationship between obesity and PAD exist. The impact of PAD development due to the presence of obesity remains largely controversial. However, the most current evidence, backed by a recent meta-analysis, suggests a potential protective role of a higher body mass index on PAD-related complications and mortality. In this review, we discuss the association between obesity and PAD development, progression, and management, and the potential pathophysiologic mechanisms linking the two diseases.

Morbidity and Mortality in Non-Obese Compared to Different Classes of Obesity in Patients Undergoing Transtibial Amputations

This study assesses the effect of obesity classes on outcomes and inpatient-hospital-cost compared to non-obese individuals undergoing below-knee amputations (BKAs). Retrospective matched-case controlled study performed on data from NIS Database. We identified three groups: N-Ob (BMI < 29.9 kg/m2; n = 3104), Ob-I/II (BMI: 30 to 39.9 kg/m2; n = 3107), and Ob-III (BMI > 40; n = 3092); matched for gender, comorbidities, tobacco use and elective vs. emergent surgery. Differences in morbidity, mortality, hospital length of stay (LOS), and total inpatient cost were analyzed. Blood loss anemia was more common in Ob-III compared to Ob-I/II patients (OR = 1.2; 95% CI = 1.1−1.4); blood transfusions were less commonly required in Ob-I/II (OR = 0.8; 95% CI = 0.7−0.9) comparatively; Ob-I/II encountered pneumonia less frequently (OR = 0.9; 95% CI = 0.4−0.9), whereas myocardial infarction was more frequent (OR = 7.0; 95% CI = 2.1−23.6) compared to N-Ob patients. Acute renal failure is more frequent in Ob-I/II (OR = 1.2; 95% CI = 1.0−1.3) and Ob-III (OR = 1.8; 95% CI = 1.6−1.9) compared to the N-Ob cohort. LOS was higher in N-Ob (13.1 ± 12.8 days) and Ob-III (13.5 ± 12.4 d) compared to Ob-I/II cohort (11.8 ± 10.1 d; p < 0.001). Mortality was 2.8%, 1.4%, and 2.9% (p < 0.001) for N-Ob, Ob-I/II, and Ob-III, respectively. Hospital charges were $22,025 higher in the Ob-III cohort. Ob-I/II is protective against peri-operative complications and death, whereas hospital cost is substantially higher in Ob-III patients undergoing BKAs.

A systematic review and meta-analysis of the effect of obesity on patients undergoing lower extremity revascularization

OBJECTIVE

In the present review, we assessed the effect of obesity on clinical outcomes for patients with peripheral arterial disease who had undergone endovascular or open lower extremity revascularization surgery.

METHODS

A systematic search strategy of MEDLINE, EMBASE, CINAHL, Web of Science, and Cochrane Library was conducted. The included studies had compared obese and nonobese cohorts with peripheral arterial disease who had undergone endovascular or open lower extremity revascularization. The outcomes included mortality, major adverse cardiovascular events, major adverse limb events, surgical site infections, endovascular access site complications, and perioperative complications.

RESULTS

Eight studies were included with 171,648 patients. The obese patients (body mass index ≥30 kg/m²) were more likely to be women, to have diabetes, and to have more cardiovascular comorbidities despite being younger. No association was found between obesity and peripheral arterial disease severity. Obesity was associated with an overall 22% decreased mortality risk after lower extremity revascularization (risk ratio [RR], 0.78; 95% confidence interval [CI], 0.71-0.85; P < .001; I² = 0%; GRADE (grading of recommendations assessment, development, evaluation), very low quality). A subgroup analysis by intervention type showed similar findings (endovascular: RR, 0.79; 95% CI, 0.71-0.87; P < .001; I² = 0%; open: RR, 0.70; 95% CI, 0.51-0.95; P = .024; I² = 43%). Obesity was associated with a 14% decreased risk of major adverse cardiovascular events for open surgery only (RR, 0.86; 95% CI, 0.76-0.98; P = .021; I² = 0%; GRADE, very low quality). Obesity was associated with an increased risk of surgical site infections pooled across intervention types (RR, 1.69; 95% CI, 1.34-2.14; P < .001; I² = 78%; GRADE, very low quality). No association was found between obesity and major adverse limb events (RR, 1.02; 95% CI, 0.93-1.11; P = .73; I² = 15%; GRADE, very low quality) or endovascular access site complications (RR, 1.11; 95% CI, 0.76-1.63; P = .58; I² = 86%; GRADE, very low quality). Pooled perioperative complications did not differ between the obese and nonobese cohorts (RR, 1.04; 95% CI, 0.84-1.28; P = .73; I² = 92%; GRADE, very low quality).

CONCLUSIONS

Obesity was associated with reduced mortality risk with both endovascular and open surgery, although a reduction in major adverse cardiovascular events was only observed with open surgery. In addition, obese patients had an increased risk of surgical site infections. Obesity was not associated with major adverse limb events, endovascular access site complications, or perioperative complications. The GRADE quality of evidence was very low. The findings from the present review suggest a survival advantage for obese patients with peripheral arterial disease. Future studies could focus on prospectively investigating the effect of obesity on peripheral arterial disease outcomes. A nuanced evaluation of body mass index as a preoperative risk factor is warranted.

Mortality risk in patients with underweight or obesity with peripheral artery disease: a meta-analysis including 5,735,578 individuals

OBJECTIVES

The "obesity paradox" - in which patients with obesity exhibit superior survival than normal-weight counterparts - has been reported for several diseases. However, obesity is a well-known risk factor for cardiovascular disease, and whether the obesity paradox is present in peripheral artery disease (PAD) is unknown.

METHODS

A comprehensive search for studies that reported mortality in patients with PAD grouped by BMI identified 12 studies. We compared the survival of underweight patients with those who were not underweight, and patients with obesity against those without. Underweight was defined by a BMI value of <18.5 kg/m² in most studies and obesity by BMI ≥ 30 kg/m². Subgroup analyses were performed according to length of follow-up, presentation of PAD, and mode of revascularization. Meta-regression analyses were conducted, with covariates including age, sex, presence of coronary artery disease (CAD) and diabetes mellitus (DM).

RESULTS

The mortality risk of underweight patients with PAD was significantly higher compared to those who are not underweight (HR 1.72, 95% CI 1.38-2.14; I² = 84.2%). In contrast, the mortality risk of patients with obesity with PAD was significantly lower than those without (HR 0.78, 95% CI 0.62-0.97; I² = 89.8%). These findings remained consistent regardless of the presentation of PAD, revascularization, age, sex, or presence of CAD. The risk of death in the short-term of underweight patients (HR 1.50, 95% CI 0.47-4.72) and patients with obesity (HR 0.86, 95% CI 0.66-1.13) were not significantly different from their counterparts. The meta-regression showed that of the association between obesity and better survival was more pronounced in studies with a greater proportion of patients with concomitant CAD (regression coefficient -0.029, 95% CI -0.054 to -0.004).

CONCLUSIONS

In patients with PAD, mortality is higher among underweight patients and lower among patients with obesity. The mechanisms underlying the obesity paradox in patients with PAD remain to be elucidated, and further evidence is required to guide optimal weight control strategies in these patients.

A Dose Response Association Between Body Mass Index and Mortality in Patients with Peripheral Artery Disease: A Meta-analysis Including 5 729 272 Individuals

OBJECTIVE

Obesity is a significant risk factor for atherosclerotic cardiovascular disease; however, the "obesity paradox", in which obese patients enjoy superior survival, has been observed in various cardiovascular conditions. Whether this phenomenon exists for peripheral artery disease (PAD) remains uncertain. The goal of this study was to evaluate the relationship between body mass index (BMI) and mortality in patients with PAD.

METHODS

A comprehensive literature search identified seven eligible cohort studies that reported the association between BMI and all cause mortality in patients with PAD. A dose response meta-analysis was done for all cause mortality, short term (30 day or in hospital) mortality and long term mortality. The dose response association between BMI and mortality was also assessed in patients who received endovascular therapy (EVT).

RESULTS

The non-linear dose response analysis showed that higher BMI values were associated with a lower mortality risk from the range between 15 kg/m² to approximately 33 - 34 kg/m². The risk of mortality increased slightly thereafter. This relationship was consistent with that of long term mortality but was not apparent in short term mortality. A U shaped relationship was also observed between BMI and mortality in patients who received EVT with the lowest mortality observed at around 30 kg/m².

CONCLUSION

The obesity paradox was evident in the analysis of long term survival among patients with PAD, with the lowest mortality rates observed in obese patients. However, this association was not observed for short term or in hospital mortality.

The Association of Body Mass Index with Outcomes after Carotid Endarterectomy

BACKGROUND

Patients who are obese or underweight are traditionally at higher risk for perioperative morbidity and mortality. The effect of body mass index (BMI) on outcomes after carotid endarterectomy (CEA) is unclear. Our goal was to analyze the association of BMI with perioperative and long-term outcomes after elective CEA.

METHODS

The Vascular Quality Initiative (VQI) database was queried from 2003-2018 for patients undergoing elective CEAs. Patients were categorized into 5 BMI cohorts - underweight (UW, BMI < 18.5 kg/m²), normal weight (NW, BMI 18.5-24.9 kg/m²), overweight (OW, BMI 25-29.9 kg/m²), obese (OB, BMI 30-39.9 kg/m²), and morbidly obese (MO, BMI ≥ 40 kg/m²). Perioperative and long-term outcomes were assessed with univariable and multivariable analyses.

RESULTS

There were 89,079 patients included: 2% UW, 26% NW, 38.4% OW, 29.9% OB, and 3.6% MO. Overall, the mean age was 70.6 years, 60% were male, and 91.8% were of white race. There were significant differences among the BMI cohorts in regards to age, sex, smoking status, and comorbidities (all P < 0.05). For perioperative outcomes, the BMI cohorts differed significantly in reoperation for bleeding and 30-day mortality. On multivariable analysis, BMI was not associated with stroke or perioperative mortality. MO was associated with perioperative cardiac complications (Odds Ratios [OR] 1.26, 95% CI 1-1.57, P = 0.05). UW status was associated with increased return to the operating room (OR 1.89, 95% confidence interval [95% CI] 1.28-2.78, P = 0.001), 30-day mortality (OR 1.68, 95% CI 1-2.86, P =0.05), 1-year mortality (Hazard ratio [HR] 1.37, 95% CI 1.08-1.74, P = 0.01), and 5-year mortality (HR 1.22, 95% CI 1.06-1.41, P =0.005).

CONCLUSIONS

BMI status was not associated with perioperative stroke, cranial nerve injury, or surgical site infections. Patients with MO had higher perioperative cardiac complications. UW patients have lower short and long-term survival and should be a focus for long-term targeted risk factor stratification and modification.

The long-term implications of access complications during endovascular aneurysm repair

BACKGROUND

Access issues are one of the most common complications of endovascular aneurysm repair (EVAR). However, contemporary rates as well as risk factors for complications and the subsequent impact of access complications on mortality are poorly described.

METHODS

We studied all EVAR for intact abdominal aortic aneurysms without prior aortic surgery in the Vascular Quality Initiative between 2011 and 2018. We studied factors associated with access complications (thrombosis, embolus, wound infection, hematoma, and conversion to cutdown), as well as the interaction with female sex and the impact on survival using multilevel logistic regression and propensity weighting. Multiple imputation was used for missing data.

RESULTS

There were 33,951 EVAR during the study period (91% elective, 9% symptomatic); most cases (70%) involved an attempt at percutaneous access on at least one side, with 30% bilateral cutdowns and 0.1% iliac conduits. There were 1553 patients (4.6%) who experienced at least one access complication. Access complications were almost twice as common in female patients (7.5% vs 3.9%; P < .001). The factors associated with access complications included female sex (odds ratio [OR], 2.7; 95% confidence interval [CI], 2.0-3.6; P < .001), age (OR, 1.05 per 5 years; 95% CI, 1.02-1.1; P < .01), aortouni-iliac device (OR, 1.6; 95% CI, 1.1-2.3; P < .01), smoking (OR, 1.4; 95% CI, 1.1-1.7; P < .01), body mass index of less than 16 (OR, 1.8; 95% CI, 1.3-2.5; P = .001), dual antiplatelet therapy (1.3; 95% CI, 1.02-1.6 P = .03), prior infrainguinal bypass (OR, 1.8; 95% CI, 1.3-2.7; P < .01), and beta blocker use (OR, 1.2; 95% CI, 1.03-1.4; P = .02). Conversion from percutaneous access to open cutdown was associated with higher rates of complications than planned open cutdown (8.6% vs 2.9%; P < .001). In propensity-weighted analysis, percutaneous access was associated with significantly lower odds of access complications in women (OR, 0.6; 95% CI, 0.4-0.96; P = .03). Patients who experienced an access complication had more than four times the odds of perioperative death (OR, 4.2; 95% CI, 2.5-7.1; P < .001), and a 60% higher risk of long-term mortality (hazard ratio, 1.6; 95% CI, 1.2-2.1; P = .001). In addition to death, patients with access site complications had higher rates of other major complications, including reoperation during the index hospitalization (19% vs 1.2%; P < .001), myocardial infarction (3.5% vs 0.7%; P < .001), stroke (0.8% vs 0.2%; P < .001), acute kidney injury (12% vs 3%; P < .001), and reintubation (5.7% vs 0.8%).

CONCLUSIONS

Although access complications are infrequent in the current era, they are associated with both perioperative and long-term morbidity and mortality. Female patients in particular are at high risk of access complications, but may benefit from percutaneous access.

Nutritional status and outcomes of superficial femoral artery stenting due to intermittent claudication

BACKGROUND

The pathogenesis of in-stent restenosis is still not clear. The aim of this study was to determine the nutritional status of patients with lower limb ischemia and the risk of target lesion revascularization (TLR) after superficial femoral artery (SFA) stenting.

METHODS

Numerous parameters of nutritional status assessment were compared between 70 patients undergoing SFA endovascular intervention with a self-expandable plane stent due to life-limiting intermittent claudication and 40 patients undergoing carotid artery stenting (CAS). All subjects were followed up for at least 1 year in relation to outcomes such as clinically driven TLR occurrence.

RESULTS

Patients undergoing SFA stenting had a lower prevalence of overweight and obesity than those who underwent CAS (51.43% vs. 72.50%; P=0.031). An increase in Ankle-Brachial Index of >0.15 after SFA stenting (early end-point) was positively associated with greater handgrip strength (HGS), fat-free mass, skeletal muscle mass and waist-to-hip ratio. Freedom from TLR (late end-point) was significantly related to a higher waist-to-height ratio (WHtR), HGS and Geriatric Nutritional Risk Index (GNRI) Score. The 1-year risk of TLR for patients with a WHtR of ≥61.39 amounted to odds ratio; 95% confidence interval: 0.21; 0.05-0.25; P=0.021.

CONCLUSIONS

Parameters of nutritional status assessment were associated with early and late outcomes of SFA stenting in patients with intermittent claudication. Abdominal fat distribution and higher HGS and GNRI scores lowered the 1-year risk of TLR. Further study is needed to determine the pathomechanism of the obesity paradox, sarcopenia and undernutrition in relation to outcomes of endovascular interventions.

Low Body Mass Index and Low Intelligence Quotient Are Infection Risk Factors in Vagus Nerve Stimulation

BACKGROUND

Risk factors for infection after vagus nerve stimulation (VNS) device implantation represent an important issue but remain unclear. We hypothesized that specific risk factors for infection would be associated with VNS device implantation. This study reviewed patients with epilepsy who underwent VNS device implantation and undertook a statistical analysis of risk factors for surgical site infection (SSI).

METHODS

We reviewed all medical records for patients who underwent VNS therapy in our facility between August 2011 and May 2018. Age, sex, height, body weight, body mass index (BMI), intelligence quotient (IQ), surgical incision opening time, blood loss, epilepsy classification, activities of daily living, and generator replacement were statistically compared between cases with and without SSI.

RESULTS

We performed 208 VNS device implantation surgeries at our facility during the study period. Among these, 150 patients underwent initial implantation, 56 patients underwent first generator replacement, and 2 patients underwent second replacement. Six patients (2.7%) with initial implantation and 3 patients (5.4%) with first replacement showed SSI. Low BMI was a risk factor for infection at initial implantation (P < 0.0012) using a BMI within 1.78 kg/m² of the cutoff for being underweight (100% sensitivity, 25% specificity). Low IQ (P = 0.0015) was also a risk factor for SSI.

CONCLUSIONS

This study identified low BMI and low IQ at initial implantation as risk factors for infection.