The impact of perioperative red blood cell transfusions on postoperative outcomes in vascular surgery patients.

BACKGROUND: Red blood cell (RBC) transfusions are common in vascular surgery and aim to reduce tissue ischemia. However, the evidence that transfusions are beneficial is contradictory. This study evaluates the impact of perioperative transfusion (transfusion within 3 days of surgery) on 30-day postoperative outcomes in elective vascular surgery patients. METHODS: This observational cohort included 1,041 vascular surgery patients between 2002 and 2011 in a tertiary referral center for whom hemoglobin levels were retrospectively available. Patients who received transfusions after 3 days postoperatively were excluded. A propensity score was developed for the likelihood of receiving perioperative transfusion. The study end points were 30-day cardiovascular (CV) events (myocardial infarction, heart failure, arrhythmias, stroke, asymptomatic troponin-T release, and CV death) and all-cause mortality. Multivariable logistic regression analyses, adjusting for relevant confounders and transfusion propensity, were used to determine the associations between perioperative transfusion and the study end points. RESULTS: The final study sample comprised 992 patients; 265 (27%) patients received perioperative transfusions. During the 30-day follow-up, a total of 190 (19%) patients suffered from a 30-day postoperative CV event, of which 116 (44%) occurred in patients who received perioperative RBC transfusions compared with 74 (10%) patients without transfusions (P < 0.01). The end point all-cause mortality was reached in 36 (4%) patients-26 (10%) patients with perioperative RBC transfusion compared with 10 (1%) patients without transfusion (P < 0.01). Perioperative transfusion was associated with an independently increased risk of 30-day CV events (odds ratio 5.0; 95% confidence interval 3.1-8.2) and all-cause mortality (odds ratio 4.4; 95% confidence interval 1.6-12.1). CONCLUSION: Perioperative transfusion is associated with a strongly increased risk of both 30-day CV events and mortality in elective vascular surgery patients.

Lower atherosclerotic burden in familial abdominal aortic aneurysm.

OBJECTIVE: Despite the apparent familial tendency toward abdominal aortic aneurysm (AAA) formation, the genetic causes and underlying molecular mechanisms are still undefined. In this study, we investigated the association between familial AAA (fAAA) and atherosclerosis. METHODS: Data were collected from a prospective database including AAA patients between 2004 and 2012 in the Erasmus University Medical Center, Rotterdam, The Netherlands. Family history was obtained by written questionnaire (93.1% response rate). Patients were classified as fAAA when at least one affected first-degree relative with an aortic aneurysm was reported. Patients without an affected first-degree relative were classified as sporadic AAA (spAAA). A standardized ultrasound measurement of the common carotid intima-media thickness (CIMT), a marker for generalized atherosclerosis, was routinely performed and patients' clinical characteristics (demographics, aneurysm characteristics, cardiovascular comorbidities and risk factors, and medication use) were recorded. Multivariable linear regression analyses were used to assess the mean adjusted difference in CIMT and multivariable logistic regression analysis was used to calculate associations of increased CIMT and clinical characteristics between fAAA and spAAA. RESULTS: A total of 461 AAA patients (85% men, mean age, 70 years) were included in the study; 103 patients (22.3%) were classified as fAAA and 358 patients (77.7%) as spAAA. The mean (standard deviation) CIMT in patients with fAAA was 0.89 (0.24) mm and 1.00 (0.29) mm in patients with spAAA (P = .001). Adjustment for clinical characteristics showed a mean difference in CIMT of 0.09 mm (95% confidence interval, 0.02-0.15; P = .011) between both groups. Increased CIMT, smoking, hypertension, and diabetes mellitus were all less associated with fAAA compared with spAAA. CONCLUSIONS: The current study shows a lower atherosclerotic burden, as reflected by a lower CIMT, in patients with fAAA compared with patients with spAAA, independent of common atherosclerotic risk factors. These results support the hypothesis that although atherosclerosis is a common underlying feature in patients with aneurysms, atherosclerosis is not the primary driving factor in the development of fAAA.

Impact of obesity on postoperative and long-term outcomes in a general surgery population: a retrospective cohort study.

BACKGROUND: The obesity paradox has been demonstrated postoperatively in several surgical populations, but only a few studies have reported long-term survival. This study evaluates the presence of the obesity paradox in a general surgery population, reporting both postoperative and long-term survival. METHODS: This retrospective study included 10,427 patients scheduled for elective, noncardiac surgery. Patients were classified as underweight (body mass index (BMI) < 18.5 kg/m(2)); normal weight (BMI 18.5-24.9 kg/m(2)); overweight (BMI 25.0-29.9 kg/m(2)); obesity class I (BMI 30.0-34.9 kg/m(2)); obesity class II (BMI 35.0-39.9 kg/m(2)); and obesity class III (BMI ≥ 40.0 kg/m(2)). Study endpoints were 30-day postoperative and long-term mortality, including cause-specific mortality. Multivariable analyses were used to evaluate mortality risks for each BMI category. RESULTS: Within 30 days after surgery, 353 (3.4 %) patients died. Overweight was the only category associated with postoperative mortality, showing improved survival [odds ratio 0.7; 95 % confidence interval (CI) 0.6-0.9]. During the long-term follow-up 4,884 (47 %) patients died. Underweight patients had the highest mortality risk [hazard ratio (HR) 1.4; 95 % CI 1.2-1.6), particularly due to high cancer-related deaths. In contrast, overweight and obese patients demonstrated improved survival (overweight: HR 0.8, 95 % CI 0.8-0.9; obesity class I: HR 0.7, 95 % CI 0.7-0.8; obesity class II: HR 0.7, 95 % CI 0.6-0.9; obesity class III: HR 0.7, 95 % CI 0.5-1.0), mainly because of a strongly reduced risk of cancer-related death. CONCLUSIONS: In this surgical population the obesity paradox was validated at the long term, mainly because of decreased cancer-related deaths among obese patients.

Impact of haemoglobin concentration on cardiovascular outcome after vascular surgery: a retrospective observational cohort study.

BACKGROUND: Although low preoperative haemoglobin (Hb) concentration is a well known risk factor for adverse outcome, little is known about decreases in Hb and postoperative Hb concentrations. OBJECTIVES: The aim of this study was to evaluate the prognostic impact of both pre- and postoperative Hb concentrations (divided into low, intermediate and high tertiles) as well as Hb decrease, defined as preoperative minus postoperative Hb (g dl(-1)), on postoperative cardiovascular events in vascular surgery patients. DESIGN: A retrospective observational cohort study. SETTING: Erasmus University Medical Centre, Rotterdam, the Netherlands, from 1 January 2002 to 31 December 2011. PATIENTS: One thousand four hundred and eighty-four patients underwent elective open or endovascular abdominal aortic repair (aneurysm or stenosis), lower extremity arterial repair or carotid surgery. Patients for whom pre or postoperative Hb concentrations were not available were excluded. MAIN OUTCOME MEASURES: The study endpoint was 30-day postoperative cardiovascular events, including myocardial infarction, heart failure, arrhythmias, stroke, asymptomatic troponin-T release and cardiovascular death. RESULTS: In 1041 patients, both pre and postoperative Hb concentrations were available. Thirty-day cardiovascular events occurred in 221 (21%) patients. Multivariable logistic regression analyses, adjusting for age, sex, Revised Cardiac Risk Index (high-risk surgery, coronary heart disease, heart failure, cerebrovascular disease, diabetes mellitus, renal insufficiency), hypertension and hypercholesterolaemia, demonstrated that low preoperative Hb (8.7 to 12.9 g dl(-1)) was associated with 30-day events [odds ratio (OR) 1.7; 95% confidence interval (CI) 1.1 to 2.5]. Intermediate (10.6 to 12.1 g dl(-1)) and low (7.4 to 10.5 g dl(-1)) postoperative Hb and Hb decrease were also associated with an independently increased risk of 30-day events (intermediate Hb: OR 1.7; 95% CI 1.1 to 2.7; low Hb: OR 3.1; 95% CI 2.0 to 4.8; and Hb decrease: OR 1.2; 95% CI 1.1 to 1.3, respectively). Sensitivity analyses excluding patients with transfusions (n=314) demonstrated that only postoperative Hb concentrations remained associated with a high risk of 30-day cardiovascular events (intermediate Hb: OR 1.8; 95% CI 1.0 to 3.3 and low Hb: OR 2.0; 95% CI 1.0 to 4.0). CONCLUSION: Pre and postoperative Hb concentrations and Hb decrease are all related to 30-day cardiovascular events in elective vascular surgery patients. Postoperative Hb concentrations are the strongest predictor of 30-day cardiovascular events.

The obesity paradox in the surgical population.

BACKGROUND: Despite the medical hazards of obesity, recent reports examining body mass index (BMI) show an inverse relationship with morbidity and mortality in the surgical patient. This phenomenon is known as the 'obesity paradox'. The aim of this review is to summarize both the literature concerned with the obesity paradox in the surgical setting, as well as the theories explaining its causation. METHODS: PubMed was searched to identify available literature. Search criteria included obesity paradox and BMI paradox, and studies in which BMI was used as a measure of body fat were potentially eligible for inclusion in this review. RESULTS: The obesity paradox has been demonstrated in cardiac and in non-cardiac surgery patients. Underweight and morbidly obese patients displayed the worse outcomes, both postoperatively as well as at long-term follow-up. Hypotheses to explain the obesity paradox include increased lean body mass, (protective) peripheral body fat, reduced inflammatory response, genetics and a decline in cardiovascular disease risk factors, but probably unknown factors contribute too. CONCLUSIONS: Patients at the extremes of BMI, both the underweight and the morbid obese, seem to have the highest postoperative morbidity and mortality hazard, which even persists at long-term. The cause of the obesity paradox is probably multi-factorial. This offers potential for future research in order to improve outcomes for persons on both sides of the 'optimum BMI'.

Aneurysmal disease is associated with lower carotid intima-media thickness than occlusive arterial disease.

OBJECTIVE: Patients with aneurysmal and occlusive arterial disease have overlapping cardiovascular risk profiles. The question remains how atherosclerosis is related to the formation of aortic aneurysms. Common carotid artery intima-media thickness (CIMT) is an easily accessible and objective marker of early atherosclerosis. The aim of the current study was to investigate whether there is a difference in atherosclerotic burden as measured by CIMT between patients with aneurysmal and those with occlusive arterial disease. METHODS: From 2004 to 2011, the CIMT was measured using B-mode ultrasound scanning in patients undergoing vascular surgery for aortic aneurysmal or occlusive arterial disease at the Erasmus University Medical Center. Cardiovascular risk factors, comorbidities, and medication were recorded. Patients treated for combined aneurysmal and occlusive arterial disease and patients diagnosed with a genetic aneurysm syndrome were excluded. Univariable and multivariable analyses were used to calculate differences in CIMT between aneurysmal and occlusive arterial disease. RESULTS: In total, 904 patients were included in the study: 502 patients with aneurysmal disease (85% male; mean age, 72 years) and 402 patients with occlusive arterial disease (65% male; mean age, 64 years). The mean (standard deviation) CIMT in patients with aneurysmal disease was 0.97 (0.29) mm and was 1.07 (0.38) mm in patients with occlusive arterial disease (P < .001). Adjustment for cardiovascular risk factors, comorbidities, and medication showed a mean difference in CIMT of 0.15 mm (95% confidence interval, 0.10-0.20; P < .001). CONCLUSIONS: The current study shows a lower CIMT in patients with aneurysmal disease than in those with occlusive arterial disease, indicating a lower atherosclerotic burden in patients with aneurysmal disease. These findings endorse the idea that additional pathogenic mechanisms are involved in aortic aneurysm formation. Further studies are needed to clarify the role of atherosclerosis in aortic aneurysm formation.

Lessons from the REACH Registry in Europe.

Among patients with atherothrombosis, including coronary artery disease (CAD), cerebrovascular disease (CVD), and peripheral arterial disease (PAD), patients with PAD generally have the worse prognosis. The Reduction of Atherothrombosis for Continued Health (REACH) Registry characterized the atherothrombotic risk factor profile, and evaluated treatment intensity and cardiovascular events among different atherothrombotic patient populations worldwide. Two thirds of PAD patients had polyvascular disease, defined as symptomatic involvement of more than one vascular bed. The risk factor profile in patients with CAD, CVD and PAD was very much similar. However, optimal risk factor control by medical treatment and lifestyle interventions was least accomplished in PAD patients. Furthermore, PAD patients and patients with polyvascular disease showed the highest cardiovascular event rates. Of note, therapeutic strategies are similar for all atherothrombotic disease categories, irrespective of the presence of polyvascular disease. Therefore, it is of the utmost importance to achieve optimal risk factor control, particularly for PAD patients and for those with polyvascular disease, in order to prevent future cardiovascular events.

Influence of aortic valve calcium on outcome in patients undergoing peripheral vascular surgery.

Vascular surgery patients are at increased risk of adverse cardiovascular events because of silent coronary artery disease and an increased propensity for left ventricular dysfunction. The Revised Cardiac Risk Index is commonly used for preoperative risk stratification. Aortic valve calcium is associated with cardiovascular mortality in the general population. The present study evaluated the prognostic implications of aortic valve calcium on 30-day postoperative and long-term outcomes in vascular surgery patients. Echocardiographic aortic valve evaluation was completed in 1,172 vascular surgery patients. Aortic valve sclerosis was defined by the presence of thickening and/or calcium of ≥1 cusps of a tricuspid aortic valve not inducing stenosis (i.e., with a maximal velocity at continuous Doppler of <2.5 m/s). Stenosis was defined as a maximum velocity of >2.5 m/s. Troponin-T measurements and electrocardiograms were performed routinely after surgery. The study end points were the composite of postoperative cardiovascular events and long-term mortality. Aortic valve sclerosis was present in 416 patients (36%), and aortic valve stenosis was present in 30 patients (3%). After multivariate regression analyses adjusted for age, gender, Revised Cardiac Risk Index, hypertension, hypercholesterolemia, and medication use, aortic valve sclerosis was not associated with either the postoperative or long-term outcomes. In contrast, aortic valve stenosis was associated with a greater postoperative and long-term event rate (odds ratio 3.9, 95% confidence interval 1.7 to 8.7; and hazard ratio 2.1, 95% confidence interval 1.2 to 3.7, respectively). In conclusion, the present study has shown that aortic valve calcium is common in vascular surgery patients. Its presence is associated with negative postoperative and long-term outcomes.

Preoperative left ventricular dysfunction predisposes to postoperative acute kidney injury and long-term mortality.

BACKGROUND: Both preoperative left ventricular dysfunction (LVD) and acute kidney injury (AKI) in the postoperative period are independently associated with mortality. We evaluated the prevalence and prognostic implications of AKI in a cohort of vascular surgery patients. METHODS: Before vascular surgery, 1,158 patients were screened for LVD. Development of AKI, defined by RIFLE classification, was detected by serial serum creatinine measurements at days 1 to 3 after surgery. Primary end point was cardiovascular mortality during a median follow-up of 2.2 years (interquartile range [IQR] 1.0-4.0). RESULTS: LVD was present in 558 patients (48%), and 120 patients (10%) developed postoperative AKI. Subjects with LVD developed postoperative AKI more often than patients without LVD (8% vs. 13%, p=0.01). Patients were categorized as (i) no LVD, without AKI (n=551, 48%), (ii) LVD without AKI (n=487, 42%), (iii) no LVD, with AKI (n=49, 4%) and (iv) LVD with AKI (n=71/6%). Patients with LVD prior to surgery who developed postoperative AKI had the highest cardiovascular mortality risk (hazard ratio = 4.9; 95% confidence interval, 2.9-8.2). CONCLUSION: Patients with preoperatively LVD have an increased risk of developing AKI after vascular surgery. The occurrence of AKI in patients with LVD has an incremental predictive value toward cardiovascular mortality risk during long-term follow-up.

Influence of left ventricular dysfunction (diastolic versus systolic) on long-term prognosis in patients with versus without diabetes mellitus having elective peripheral arterial surgery.

Diabetes mellitus (DM) and left ventricular dysfunction (LVD) are often coexistent and invariably associated with increased mortality. Data on long-term prognosis of "isolated" diastolic LVD in diabetics are lacking; therefore, we evaluated these prognostic implications in patients with peripheral arterial disease (PAD) and DM. Using echocardiography, 1321 patients were screened for diastolic, systolic (ejection fraction <50%) or combined LVD. Diastolic LVD was diagnosed based on the ratio of early rapid filling to late filling due to atrial contraction, pulmonary vein flow, and deceleration time. Patients using glucose-lowering drugs or insulin or with a fasting glucose level >6.1 mmol/L were diagnosed with DM. The primary end point was occurrence of cardiovascular death during a mean follow-up of 2.5 +/- 1.9 years. In the total population, DM was diagnosed in 518 patients (39%), and diastolic, systolic, or combined LVD was present in 356 patients (27%), 102 patients (8%), or 156 patients (12%), respectively. In diabetic patients, diastolic and systolic LVDs were associated with increased cardiovascular mortality (hazard ratio 1.8, 95% confidence interval 1.03 to 3.03; hazard ratio 3.1, 95% confidence interval 1.46 to 6.38). In nondiabetic patients, the same association between diastolic or systolic LVD and outcome was observed (hazard ratio 2.2, 95% confidence interval 1.30 to 3.74; hazard ratio 3.9, 95% confidence interval 2.00 to 7.52). Combined systolic and diastolic LVD had the worst prognosis. In conclusion, diabetic patients with PAD have an increased prevalence of isolated systolic and combined LVD. In patients with PAD the presence of isolated diastolic, systolic, or combined LVD was independently and equally associated with increased cardiovascular mortality, irrespective of the concomitant presence of DM.

Elevated preoperative phosphorus levels are an independent risk factor for cardiovascular mortality.

BACKGROUND/AIMS: Serum phosphorus levels have been associated with adverse long-term outcome in several populations, however, no prior studies evaluated short-term postoperative outcome. The present study evaluated the predictive value of phosphorus levels on 30-day outcome after vascular surgery. METHODS: The study included patients scheduled for major vascular surgery (aortic aneurysm repair, lower extremity revascularization or carotid surgery), divided into four quartiles based on the preoperative fasting phosphorus level. The endpoints of the analyses were all-cause and cardiovascular mortality during the first 30 postoperative days and during long-term follow-up (median 3.6 years, interquartile range 1.8-8.0). RESULTS: Prior to surgery, 1,798 patients were categorized into the following quartiles: <2.9 mg/dl (n = 459), 2.9-3.4 mg/dl (n = 456), 3.4-3.8 mg/dl (n = 444) and >3.8 mg/dl (n = 439), respectively. During the first 30 postoperative days, 81 (4.5%) patients died of which 66 (81%) secondary to a cardiovascular cause. In multivariate analyses, an independent association was observed between phosphorus level >3.8 mg/dl and all-cause (OR 2.53, 95% CI 1.2-5.4) or cardiovascular mortality (OR 2.37, 95% CI 1.1-5.7). Baseline serum phosphorus >3.8 mg/dl was also significantly associated with long-term all-cause mortality (HR 1.38, 95% CI 1.1-1.7). CONCLUSIONS: Preoperative elevated serum phosphorus demonstrated an independent relationship with the occurrence of all-cause and cardiovascular mortality during the first 30 days after major vascular surgery. In addition, an elevated serum phosphorus was independently associated with long-term mortality.