Relationship of unrecognised myocardial infarction, diabetes mellitus and type of surgery to postoperative cardiac outcomes in vascular surgery

Whole body cardiovascular magnetic resonance imaging to stratify symptomatic and asymptomatic atherosclerotic burden in patients with isolated cardiovascular disease

Background

The aim of this study was to use whole body cardiovascular magnetic resonance imaging (WB CVMR) to assess the heart and arterial network in a single examination, so as to describe the burden of atherosclerosis and subclinical disease in participants with symptomatic single site vascular disease.

Methods

64 patients with a history of symptomatic single site vascular disease (38 coronary artery disease (CAD), 9 cerebrovascular disease, 17 peripheral arterial disease (PAD)) underwent whole body angiogram and cardiac MR in a 3 T scanner. The arterial tree was subdivided into 31 segments and each scored according to the degree of stenosis. From this a standardised atheroma score (SAS) was calculated. Cine and late gadolinium enhancement images of the left ventricle were obtained.

Results

Asymptomatic atherosclerotic disease with greater than 50 % stenosis in arteries other than that responsible for their presenting complain was detected in 37 % of CAD, 33 % of cerebrovascular and 47 % of PAD patients. Unrecognised myocardial infarcts were observed in 29 % of PAD patients. SAS was significantly higher in PAD patients 24 (17.5-30.5) compared to CAD 4 (2–11.25) or cerebrovascular disease patients 6 (2-10) (ANCOVA p < 0.001). Standardised atheroma score positively correlated with age (β 0.36 p = 0.002), smoking status (β 0.34 p = 0.002), and LV mass (β -0.61 p = 0.001) on multiple linear regression.

Conclusion

WB CVMR is an effective method for the stratification of cardiovascular disease. The high prevalence of asymptomatic arterial disease, and silent myocardial infarctions, particularly in the peripheral arterial disease group, demonstrates the importance of a systematic approach to the assessment of cardiovascular disease.

Follow-up of atheroma burden with sequential whole body contrast enhanced MR angiography: a feasibility study

Assess the feasibility of whole body magnetic resonance angiography (WB-MRA) for monitoring global atheroma burden in a population with peripheral arterial disease (PAD). 50 consecutive patients with symptomatic PAD referred for clinically indicated MRA were recruited. Whole body MRA (WB-MRA) was performed at baseline, 6 months and 3 years. The vasculature was split into 31 anatomical arterial segments. Each segment was scored according to degree of luminal narrowing: 0 = normal, 1 = <50 %, 2 = 50–70 %, 3 = 71–99 %, 4 = vessel occlusion. The score from all assessable segments was summed, and then normalised to the number of assessable vessels. This normalised score was divided by four (the maximum vessel score) and multiplied by 100 to give a final standardised atheroma score (SAS) with a score of 0–100. Progression was assessed with repeat measure ANOVA. 36 patients were scanned at 0 and 6 months, with 26 patients scanned at the 3 years follow up. Only those who completed all three visits were included in the final analysis. Baseline atherosclerotic burden was high with a mean SAS of 15.7 ± 10.3. No significant progression was present at 6 months (mean SAS 16.4 ± 10.5, p = 0.67), however there was significant disease progression at 3 years (mean SAS 17.7 ± 11.5, p = 0.01). Those with atheroma progression at follow-up were less likely to be on statin therapy (79 vs 100 %, p = 0.04), and had significantly higher baseline SAS (17.6 ± 11.2 vs 10.7 ± 5.1, p = 0.043). Follow up of atheroma burden is possible with WB-MRA, which can successfully quantify and monitor atherosclerosis progression at 3 years follow-up.

The impact of diabetes on postoperative outcomes following lower-extremity bypass surgery

OBJECTIVE

The effect of diabetes type (noninsulin dependent vs insulin dependent) on outcomes after lower-extremity bypass (LEB) has not been clearly defined. Therefore, we analyzed associations between diabetes type and outcomes after LEB in patients with critical limb ischemia.

METHODS

We performed a retrospective analysis of 1977 infrainguinal LEB operations done for critical limb ischemia between 2003 and 2010 within the Vascular Study Group of New England. Patients were categorized as nondiabetic (ND), noninsulin-dependent diabetic (NIDD), or insulin-dependent diabetic (IDD) based on their preoperative medication regimen. Our main outcome measures were in-hospital mortality and major adverse events (MAEs)--a composite outcome, including myocardial infarction, dysrhythmia, congestive heart failure, wound infection, renal insufficiency, and major amputation. We compared crude and adjusted rates of mortality and MAEs using logistic regression across diabetes categories.

RESULTS

Overall, 41% of patients were ND, 28% were NIDD, and 31% were IDD. Crude rates of in-hospital mortality were similar across these groups (1.7% vs 3.1% vs 2.1%; P = .211). Adjusted analyses accounting for differences in patient characteristics showed that diabetes is not associated with increased risk of in-hospital mortality. However, type of diabetes was associated with a higher risk of MAEs in both crude (15.1% for ND; 21.1% for NIDD; and 25.2% for IDD; P < .001) and adjusted analyses (odds ratio for NIDD, 1.41; 95% confidence interval, 1.2-1.7; odds ratio for IDD, 1.53; 95% confidence interval, 1.3-1.8).

CONCLUSIONS

Diabetes is a significant contributor to the risk of postoperative complications after LEB surgery, and insulin dependence is associated with higher risk. Quality measures aimed at limiting complications after LEB may have the most impact if these initiatives are focused on patients who are IDD.

Perioperative and long-term morbidity and mortality after above-knee and below-knee amputations in diabetics and nondiabetics

We performed a retrospective review of a vascular surgery quality assurance database to evaluate the perioperative and long-term morbidity and mortality of above-knee amputations (AKA, n = 234) and below-knee amputations (BKA, n = 720) and to examine the effect of diabetes mellitus (DM) (181 of AKA and 606 of BKA patients). All patients in the database who had AKA or BKA from 1990 to May 2001 were included in the study. Perioperative 30-day cardiac morbidity and mortality and 3-yr and 10-yr mortality after AKA or BKA were assessed. The effect of DM on 30-day cardiac outcome was assessed by multivariate logistic regression and the effect on long-term survival was assessed by Cox regression analysis. The perioperative cardiac event rate (cardiac death or nonfatal myocardial infarction) was at least 6.8% after AKA and at most 3.6% after BKA. Median survival was significantly less after AKA (20 mo) than BKA (52 mo) (P < 0.001). DM was not a significant predictor of perioperative 30-day mortality (odds ratio, 0.76 [0.39-1.49]; P = 0.43) or 3-yr survival (Hazard ratio, 1.03 [0.86-1.24]; P = 0.72) but predicted 10-yr mortality (Hazard ratio, 1.34 [1.04-1.73]; P = 0.026). Significant predictors of the 30-day perioperative mortality were the site of amputation (odds ratio, 4.35 [2.56-7.14]; P < 0.001) and history of renal insufficiency (odds ratio, 2.15 [1.13-4.08]; P = 0.019). AKA should be triaged as a high-risk surgery while BKA is an intermediate-risk surgery. Long-term survival after AKA or BKA is poor, regardless of the presence of DM.

The relation between hyperglycemia and outcomes in 2,471 patients admitted to the hospital with community-acquired pneumonia

OBJECTIVE

To examine whether hyperglycemia at the time of presentation was associated with outcomes in patients admitted to non-intensive care settings with community-acquired pneumonia (CAP).

RESEARCH DESIGN AND METHODS

Prospective cohort study of consecutive patients admitted to six hospitals between 15 November 2000 and 14 November 2002.

RESULTS

Of the 2,471 patients in this study (median age 75 years), 279 (11%) had serum glucose at presentation >11 mmol/l: 178 of the 401 patients (44%) with a prior diagnosis of diabetes and 101 of the 2,070 patients (5%) without a history of diabetes. Of patients hospitalized with CAP, 9% died and 23% suffered an in-hospital complication. Compared with those with values < or =11 mmol/l, patients with an admission glucose >11 mmol/l had an increased risk of death (13 vs. 9%, P = 0.03) and in-hospital complications (29 vs. 22%, P = 0.01). Compared with those patients with admission glucose < or =6.1 mmol/l, the mortality risk was 73% higher (95% CI 12-168%) and the in-hospital complication risk was 52% higher (12-108%) in patients with admission glucose >11 mmol/l. Even after adjustment for factors in the Pneumonia Severity Index, hyperglycemia on admission remained significantly associated with subsequent adverse outcomes: for each 1-mmol/l increase, risk of in-hospital complications increased 3% (0.2-6%).

CONCLUSIONS

Hyperglycemia on admission is independently associated with adverse outcomes in patients with CAP, with the increased risks evident at lower glucose levels than previously reported.

Diabetes and coronary artery bypass surgery: an examination of perioperative glycemic control and outcomes

OBJECTIVE

To determine the adequacy of perioperative glycemic control in diabetic patients undergoing coronary artery bypass grafting (CABG) and to explore the association between glycemic control and in-hospital morbidity/mortality.

RESEARCH DESIGN AND METHODS

Retrospective cohort study of consecutive patients with diabetes undergoing CABG between April 2000 and March 2001 who survived at least 24 h postoperatively.

RESULTS

Of the 291 patients in this study, 95% had type 2 diabetes and 40% had retinopathy, nephropathy, or neuropathy at baseline. During hospitalization (median 7 days), 78 (27%) of these patients suffered a nonfatal stroke or myocardial infarction, septic complication, or died ("adverse outcomes"). Glycemic control was suboptimal (average glucose on first postoperative day was 11.4 [11.2-11.6] mmol/l) and was significantly associated with adverse outcomes post-CABG (P = 0.03). Patients whose average glucose level was in the highest quartile on postoperative day 1 had higher risk of adverse outcomes after the first postoperative day than those with glucose in the lowest quartile (odds ratio 2.5 [1.1-5.3]). Even after adjustment for other clinical and operative factors, average blood glucose level on the first postoperative day remained significantly associated with subsequent adverse outcomes: for each 1-mmol/l increase above 6.1 mmol/l, risk increased by 17%.

CONCLUSIONS

Perioperative glycemic control in our cohort of diabetic patients undergoing CABG in a tertiary care facility was suboptimal. We believe closure of this care gap is imperative, because hyperglycemia in the first postoperative day was associated with subsequent adverse outcomes in our study patients.