Comparison of cardiac morbidity between aortic and infrainguinal operations

Risk and outcomes of fracture in peripheral arterial disease patients: two nationwide cohort studies

Using national insurance claims data of Taiwan, we found that patients with peripheral arterial disease (PAD) had increased risk of fracture during the follow-up period of 2000-2013. History of PAD was also associated with adverse outcomes in hospitalized fracture patients. Prevention strategies were needed in this susceptible population.

INTRODUCTION

Limited information was available on the association between PAD and fracture. The purpose of this study is to evaluate fracture risk and post-fracture outcomes in patients with PAD.

METHODS

We identified 6647 adults aged ≥ 20 years with newly diagnosed PAD using the Taiwan National Health Insurance Research Database in 2000-2004. Comparison cohort consisted of 26,588 adults without PAD randomly selected with frequency matching in age and sex. Events of fracture were identified during the follow-up period from January 1, 2000 until December 31, 2013, to evaluate adjusted hazard ratios (HR) and 95% confidence interval (CI) of fracture associated with PAD. Another nested cohort study of 799,463 hospitalized fracture patients analyzed adjusted odds ratios (ORs) and 95% CIs of adverse events after fracture among patients with and without PAD in 2004-2013.

RESULTS

Incidences of fracture in people with and without PAD were 22.1 and 15.5 per 1000 person-years, respectively (P < .0001). Compared with control, the adjusted HR of fracture was 1.59 (95% CI, 1.48-1.69) for PAD patients. In the nested cohort study, patients with PAD had higher post-fracture mortality (OR = 1.16; 95% CI, 1.09-1.25) and various complications. PAD patients also had comparatively higher medical expenditure (2691 vs. 2232 USD, P < .0001) and longer hospital stay (10.6 vs. 9.0 days, P < 0.0001) during fracture admission.

CONCLUSIONS

Increased risk of fracture and post-fracture adverse outcomes were associated with PAD. This susceptible population needs care to prevent fracture and to minimize adverse outcomes after it occurs.

The Preoperative Evaluation of the Patient With Cardiac Risk Factors for Noncardiac Surgery: Which Patients Need Further Cardiac Risk Stratification Tests?

Cardiac risk stratification tests should be pursued only in the subgroup of patients who have a moderate to high incidence of significant coronary artery disease and only in those who will gain long-term benefit from coronary revascularization if they are found to have significant coronary artery disease. Furthermore, car diac risk stratification tests should be pursued only if the perioperative mortality and morbidity from com bined coronary revascularization followed by noncar diac surgery is not significantly higher than proceeding straight to noncardiac surgery alone. Indentification of the subgroup of patients who will need cardiac strati fication tests should be based on integration of the patient's cardiac risk factors and functional capacity with the risk and stress of the particular surgery.

Hypoxia-induced inflammation and purinergic signaling in cross clamping the human aorta

Open aortic surgery evokes a systemic inflammatory response and is associated with high morbidity and mortality. Purinergic signaling has been shown to be crucial for maintaining vascular integrity and attenuating inflammation related to hypoxia. The involvement of purinergic signaling in cross clamping of major human arteries is unknown. Our aim was to compare systemic inflammatory responses and hypoxia-induced purinergic signaling in patients undergoing either open infra-renal abdominal aortic repair or infra-inguinal revascularization. Pre- and 24 h post-operative blood samples were gathered from 6 patients undergoing aortic clamping and 6 similar patients undergoing common femoral artery cross-clamping. Using Biorad Multipex™ 21- and 27-panels 48 different cytokines, chemokines and growth factors were analyzed, in addition to circulating levels of ATP, ADP, CD39, CD73 and HIF-1α, and compared between the groups. Several inflammatory cytokines were elevated from baseline levels after aortic clamping, but not after femoral cross clamping. Most pronoun rises were seen in IL-6 (667 %, P = 0.016) and HGF (760 %, P = 0.016). HIF-1α values showed a steady increase after clamping of either artery unless the subject underwent blood transfusion. Despite an adequate increase in HIF-1α CD39 and CD73 activity decreased significantly after aortic clamping (P = 0.047 and P = 0.016, respectively). Aortic clamping is associated with a clear and strong systemic inflammatory response and impaired repair mechanisms in terms of purinergic signaling. Patients undergoing open aorta repair could benefit from pre-operative medical therapy, which enhances CD73 expression.

Effects of statins on the prognosis of local and locally advanced renal cell carcinoma following nephrectomy

The anti-angiogenic properties of statins, widely used for the treatment of hyperlipidemia, have recently been reported. The aim of this study was to investigate the effects of use of statins for the management of post-operative recurrence and progression of renal cell carcinoma (RCC). Of 306 patients diagnosed with kidney cancer between January, 2006 and June, 2012, 115 patients who showed no distant metastasis and had undergone radical or partial nephrectomy were selected. These patients were divided into a group that took statins and a group that did not. The effects of statins on the progression and recurrence of renal cancer were retrospectively analyzed. The demographics of the statins group showed that there were more males (P=0.039) and that they were of older age [mean age, 65.24 (±6.82) vs. 58.95 (±12.33) years; P=0.039] and of higher body mass index (BMI) [26.17 (±2.96) vs. 24.24 (±3.35), P=0.017]. Recurrence-free survival in the two groups showed 59.44 and 66.72 months for the statin and non-statin groups, respectively, with no statistically significant difference (P=0.586). Progression-free survival also showed no statistically significant difference between the two groups (P=0.307). Results of the multivariate analysis using Cox's regression model revealed that gender, age and BMI had no significance as prognostic factors for the recurrence and progression of renal cancer (P>0.05). Findings of the present study demonstrated that statins do not have a marked effect on the recurrence and progression of renal cancer. Therefore, further investigation using a larger patient group should be conducted for future statistical analysis.

Peak postoperative troponin levels outperform preoperative cardiac risk indices as predictors of long-term mortality after vascular surgery Troponins and postoperative outcomes

BACKGROUND

The utility of postoperative troponins as an independent predictor of long-term mortality after vascular surgery is unknown.

METHODS

One hundred sixty-four consecutive patients underwent vascular surgery and postoperative mortality was determined at 2.5 years. Troponins were drawn within 48 hours postsurgery and the peak levels, defined by the upper reference limit (URL), were categorized as negative (<URL), low positive (≥URL but <3 times the URL), or high positive (≥ 3 times the URL). A logistic regression model comprised all univariate predictors of long-term mortality and included peak troponin levels and the number of the preoperative revised cardiac risks.

RESULTS

Mortality in the high positive (n = 44), low positive (n = 41), and negative (n = 79) troponin groups was 46%, 17%, and 6%, respectively (P < .05). Independent predictors of long-term mortality were peak postoperative troponins (odds ratio [OR], 8.85; 95% confidence interval [CI], 3.29-23.81; P < .001), tissue loss (OR, 2.87; 95% CI, 1.03-8.00; P = .043), and use of statins (OR, 0.19; 95% CI, 0.07-0.49; P < .001). The c index for peak troponin levels was 0.75 (95% CI, 0.68-0.82; P < .01) and outperformed the Revised Cardiac Risk Index for predicting long-term outcomes.

CONCLUSIONS

Among patients undergoing vascular surgery, an elevated postoperative troponin level provides incremental value in predicting long-term outcomes, when compared with standard preoperative cardiac and surgical risks.

Emergency Abdominal Aortic Aneurysm Repair in a Patient with Failing Heart: Axillofemoral Bypass Using a Centrifugal Pump Combined with Levosimendan for Inotropic Support

We describe the case of an 83-year-old patient requiring repair of a large symptomatic abdominal aortic aneurysm (AAA). The patient was known to have coronary artery disease (CAD) with symptoms and signs of significant myocardial dysfunction, left-heart failure, and severe aortic insufficiency. The procedure was performed with the help of both mechanical and pharmacological circulatory support. Distal perfusion was provided by an axillofemoral bypass with a centrifugal pump, with dobutamine and levosimendan administered as pharmacological inotropic support. The patient's hemodynamic status was monitored with continuous cardiac output monitoring and transesophageal echocardiography. No serious circulatory complications were recorded during the perioperative and postoperative periods. This paper suggests a potential novel approach to combined circulatory support in patients with heart failure, scheduled for open abdominal aortic aneurysm repair.

Culprit coronary lesions requiring percutaneous coronary intervention after vascular surgery often arise from in-stent restenosis of bare metal stents

BACKGROUND

The natural history of coronary artery disease (CAD) after vascular surgery is poorly defined. The aim of this study was to determine the temporal change of coronary artery lesions requiring revascularization with a percutaneous coronary intervention (PCI) after elective vascular surgery and to determine the utility of preoperative biomarkers on predicting those patients at risk for new coronary lesions.

METHODS

The Coronary Artery Revascularization Prophylaxis Trial tested the long-term survival benefit of coronary artery revascularization before elective vascular surgery. Among randomized patients who subsequently required PCI after surgery, the stenosis of the culprit lesion from the follow-up angiogram was compared with the preoperative vessel stenosis at the identical site on the baseline angiogram.

RESULTS

A total of 30 patients underwent PCI for progressive symptoms at a median of 11.5 (interquartiles: 4.5-18.5) months postsurgery. Of 30 patients, 16 (53%) had nonobstructive CAD preoperatively (group 1) with a stenosis that increased from 17 +/- 6% to 91 +/- 2% (P < 0.01) and 14 (47%) had severe CAD at the culprit site preoperatively (group 2), with a stenosis that increased 89 +/- 2% (P = 0.15). The only biomarker that was an identifier of early coronary artery lesion formation in group 1 compared with group 2 patients was a higher baseline homocysteine level (14.6 +/- 1.4 vs. 10.6 +/- 0.7 mg/dL; P = 0.02).

CONCLUSIONS

Culprit coronary artery lesions requiring PCI after an elective vascular operation often arise from in-stent restenosis. Therapies that either stabilize existing plaques or prevent restenosis, particularly among patients with elevated homocysteine levels, have the greatest promise for improving postoperative outcomes.

The role of statins in cancer therapy

Administration of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, or statins, to ambulatory patients is associated with a lower incidence of long-term adverse cardiovascular events, including death, myocardial infarction, stroke, atrial fibrillation, and renal dysfunction. However, increasing clinical evidence suggests that statins, independent of their effects on serum cholesterol levels, may also play a potential role in the prevention and treatment of cancer. Specifically, statins have been shown to exert several beneficial antineoplastic properties, including decreased tumor growth, angiogenesis, and metastasis. The feasibility and efficacy of statins for the prevention and treatment of cancer is reviewed.

Postoperative outcomes for patients undergoing elective revascularization for critical limb ischemia and intermittent claudication: a subanalysis of the Coronary Artery Revascularization Prophylaxis (CARP) trial

OBJECTIVE

To determine the perioperative mortality, myocardial infarction rate, and long-term survival of patients with critical limb ischemia (CLI) compared with those with intermittent claudication (IC) within a cohort selected for significant coronary artery disease, a secondary analysis was conducted of a prospective, randomized, multicenter trial of Coronary Artery Revascularization Prophylaxis (CARP) before peripheral vascular surgery. This multicenter trial was sponsored by the Cooperative Studies Program of the Department of Veterans Affairs.

METHODS

Of the 510 patients enrolled in the CARP trial and randomized to coronary revascularization or no revascularization before elective vascular surgery, 143 had CLI and 164 had IC as an indication for lower limb revascularization; >95% of each group were men. The presence of coronary artery disease was determined by cardiac catheterization. Eligible patients had at least one treatable coronary lesion of > or =70%. Those with significant left main disease, ejection fraction of <20%, and aortic stenosis were excluded. Patients were randomized to coronary artery disease revascularization or no revascularization before vascular surgery and followed for mortality and morbidity perioperatively and for a median of 2.7 years postoperatively. Medical treatment of coronary artery disease was pursued aggressively.

RESULTS

Patients with IC had a longer time from randomization to vascular surgery (p = .001) and more abdominal operations (p < .001). Patients with CLI had more urgent operations (p = .006), reoperations (p < .001), and limb loss (p = .008) as well as longer hospital stays (p < .001). The IC group had more perioperative myocardial infarctions (CLI, 8.4%; IC, 17.1%; p = .024), although perioperative mortality was similar (CLI, 3.5%; IC, 1.8%; p = .360). In follow-up, the IC group also had numerically more myocardial infarctions (CLI, 16.8%; IC, 25%; p = .079), but mortality was not different (CLI, 21%; IC, 22%; p = .825). Coronary artery revascularization did not lower perioperative or long-term mortality in either group.

CONCLUSIONS

Our data indicate that patients with significant coronary artery disease and either CLI or IC can undergo vascular surgery with low mortality and morbidity, and these results are not improved by coronary artery revascularization before vascular surgery. Furthermore, when selected for the presence of symptomatically stable, severe coronary artery disease, there is no difference in long-term survival between patients with CLI and IC. Finally, the better-than-predicted outcomes for these patients with advanced systemic atherosclerosis may be due to aggressive medical management with beta-blockers, statins, and acetylsalicylic acid.

Preoperative cardiac evaluation does not improve or predict perioperative or late survival in asymptomatic diabetic patients undergoing elective infrainguinal arterial reconstruction

OBJECTIVE

Patients undergoing infrainguinal arterial reconstruction frequently have increased cardiac risk factors. Diabetic patients are often asymptomatic despite advanced cardiac disease. This study investigates whether preoperative cardiac testing improves the outcome in diabetic patients at risk for cardiac disease.

METHODS

We retrospectively reviewed all patients undergoing lower-extremity arterial reconstructions in a 32-month period from July 1999 to February 2002. Of the 433 patients identified undergoing 539 procedures, 295 had diabetes mellitus and considered in this study. The patients were stratified into two groups according to the present American College of Cardiology, American Heart Association (ACC/AHA) algorithm. We identified 140 patients with two or more of ACC (Eagle) criteria who met the inclusion criteria for a preoperative cardiac evaluation. These patients were separated into two groups: those undergoing a cardiac work-up (WU) according to the ACC/AHA algorithm and those not undergoing the recommended work-up (NWU). Outcomes included perioperative mortality, postoperative myocardial infarction, congestive heart failure, arrhythmia, and length of hospitalization. Significance of association was assessed by the Fisher exact test. Length of hospitalization was compared using the Kruskal-Wallis rank sum test. Survival data was analyzed with the Kaplan-Meier method.

RESULTS

One hundred forty patients met the criteria for moderate risk. There were 61 patients in the NWU group and 79 in the WU group. Ten patients in the WU group underwent preoperative coronary revascularization (6 had percutaneous transluminal coronary angioplasty, 4 underwent coronary artery bypass grafting). There was no difference between perioperative mortality (WU, 1%; NWU, 2%; P = 1.00) or in postoperative cardiac morbidity, including myocardial infarction, congestive heart failure, and arrhythmia requiring treatment (WU, 5%; NWU, 6%; P = .71). There were no perioperative deaths and one episode of congestive heart failure in the group that had preoperative coronary revascularization. Median length of hospitalization was 10 days in the WU group and 8 days in the NWU group ( P = .11). Patient survival at 12 months for the NWU, WU, and revascularized groups was 85.3%, 78.5%, and 80.0%, respectively; 36-month survival was 73.6%, 62.9%, and 80.0%, respectively. The three survival curves did not differ significantly ( P = .209).

CONCLUSIONS

Preoperative cardiac evaluation, as defined by the ACC/AHA algorithm, does not predict or improve postoperative morbidity, mortality, or 36-month survival in asymptomatic, diabetic patients undergoing elective lower-extremity arterial reconstruction. These data do not support the current ACC/AHA recommendations as a standard of care for diabetic patients with an intermediate clinical predictor who undergo peripheral arterial reconstruction, a high-risk surgical procedure.

Intraoperative management: peripheral vascular surgery

Lower extremity atherosclerotic disease affects nearly 10 million people in the United States. Recent advances in diagnostic imaging and interventional techniques help many patients avoid more invasive surgical procedures. Those reaching the operating room, however,represent a distilled subset of patients who are prone to significant comorbidities. We outline current treatment strategies and discuss anesthetic concerns and techniques for these complex patients.

Perioperative cardiovascular risk stratification of patients with diabetes who undergo elective major vascular surgery

BACKGROUND

The importance of diabetes mellitus (DM) as an independent risk factor for perioperative cardiac morbidity after vascular surgery is controversial. This study examined the impact of DM on perioperative outcomes and length of stay in patients who underwent major vascular surgery.

METHODS

Patients who underwent elective aortic reconstruction (n = 2792), lower extremity bypass (n = 3838), carotid endarterectomy (n = 5522), and major amputation (n = 3883) from 1997 to 1999 were identified in the National Surgical Quality Improvement Program database of the Department of Veterans Affairs. Outcomes assessed were death, cardiovascular complications (myocardial infarction, stroke, need for cardiopulmonary resuscitation), and length of stay. Multivariable logistic and linear regression models were used to control for patient demographics, procedure type, comorbidities, and diabetic complications.

RESULTS

Before adjustment for potential confounders, patients with diabetes had a higher incidence rate of perioperative death (3.9% versus 2.6%; P =.001) and cardiovascular complications (3.3% versus 2.6%; P =.01) when compared with patients without diabetes. After controlling for comorbid conditions, procedure type, and diabetic complications, only patients with DM who underwent treatment with insulin were at statistically increased risk for cardiovascular complications (odds ratio [OR], 1.48; 95% CI, 1.15 to 1.91). Neither DM treated with insulin (OR, 1.10; 95% CI, 0.85 to 1.41) nor DM treated with oral medications (OR, 0.96; 95% CI, 0.73-1.28) was an independent risk factor for death. Important independent risk factors for death included several conditions that are commonly associated with diabetes, including proteinuria, elevated creatinine level, history of congestive heart failure, and history of cerebrovascular accident. DM was also found to increase length of stay by as much as 38% even after adjustment for comorbidities.

CONCLUSION

Patients with diabetes have a higher incidence rate of death and cardiovascular complications. However, after controlling for specific comorbid conditions, the only independent association was between patients with insulin treatment and the risk of cardiovascular complications. DM does not appear to be an independent risk factor for postoperative mortality. All patients with diabetes, regardless of insulin use, have a prolonged length of stay after major vascular surgery.

Randomized study comparing cardiac response in endovascular and open abdominal aortic aneurysm repair

BACKGROUND

The aim was to compare the cardiac response and the incidence of adverse cardiac events during and after endovascular (EVAR) and open (OR) repair of abdominal aortic aneurysms (AAAs).

METHODS

Seventy-six patients with an AAA suitable for EVAR, and in a general condition allowing open surgery were randomized to EVAR (57 patients) or OR (19 patients). The analysis was on an intention-to-treat basis. Haemodynamic variables were assessed intraoperatively before, during and after aortic occlusion. During the procedure myocardial ischaemia was identified with use of electrocardiography (ECG) and transoesophageal echocardiography (TEE). After operation, cardiac complications were diagnosed by clinical observation, 12-lead ECG at 1 h, 1 day and 7 days, echocardiography at 1 month and measurement of cardiac enzymes.

RESULTS

After aortic occlusion, a greater decrease in systemic vascular resistance compared with baseline was observed with OR than with EVAR (- 396 and - 70 dyne s/cm5 respectively; P = 0.03). The stroke work index, as a direct measure of myocardial performance, demonstrated a decrease during OR and an increase during EVAR during aortic occlusion (- 6.6 and + 1.7 g m/m2 respectively; P = 0.03) as well as after aortic occlusion (- 7.6 and + 3.4 g m/m2 respectively; P < 0.01), compared with baseline. The incidence of postoperative clinical cardiac complications was comparable in the two study groups; however, myocardial ischaemia, as observed by ECG and TEE, was observed more frequently in the OR group (ten of 19 versus 15 of 57 patients; P = 0.05).

CONCLUSION

Haemodynamic changes were less severe and there was a lower incidence of myocardial ischaemia during EVAR than during OR. Studies are needed to demonstrate whether this may reduce the operative mortality rate.

Preoperative treatment with recombinant human growth hormone prevents ischemia reperfusion-induced diaphragmatic dysfunction

BACKGROUND

Respiratory complications continue to be a major cause of morbidity and mortality following major vascular surgery. The recent UK Small Aneurysm Trial cited preoperative respiratory function as the major predictor of outcome following elective aortic surgery.

AIM

The aim of this study was to investigate the effect of aortic clamping and revascularization on diaphragmatic muscle function in a small animal model and to evaluate the role of preoperative treatment with recombinant human growth hormone (rhGH) in preventing diaphragmatic muscle dysfunction.

METHODS

Male Sprague-Dawley rats (n = 18) were randomized into one of three groups: control (n = 6) underwent laparotomy only; IR (n = 6) had a laparotomy with infrarenal cross-clamping for 30 min followed by lower torso revascularization for 2 h; IR + rhGH (n = 6) were treated with rhGH (Genotropin 0.3 IU/kg/day) for 5 days before laparotomy and aortic cross-clamping for 30 min followed by lower torso revascularization for 2 h. Diaphragmatic muscle contractile function was assessed ex vivo using electrical field stimulation in a tissue bath.

RESULTS

Two hours of IR injury resulted in a significant impairment in diaphragmatic twitch (Control, 242.01 + 38.45 g; IR, 108.55 + 7.15 g). This impairment was prevented by pretreatment with rhGH (rhGH, 319.14 + 30.71 g; P < 0.01). Tetanic function was also significantly impaired by ischemia reperfusion injury (control, 605 + 77.63 g; IR, 228.12 + 14.38 g). Again, pretreatment with rhGH prevented this deterioration (IR + rhGH, 704.39 + 45.69 g; P < 0.05) compared with controls.

CONCLUSION

The results of this study suggest that preoperative administration of rhGH may have a role in preventing the diaphragmatic dysfunction associated with infrarenal aortic cross-clamping and revascularization.

An abnormal dipyridamole thallium/sestamibi fails to predict long-term cardiac events in vascular surgery patients

Recent data demonstrate that dipyridamole-thallium (DTHAL) and sestamibi (DMIBI) are not predictive of adverse perioperative cardiac events in moderate-risk patients (one or more Eagle risk factors) undergoing major elective vascular surgery. Less data are available regarding the ability of DTHAL/DMIBI to predict adverse cardiac events on long term follow-up. We sought to determine whether an abnormal DTHAL/DMIBI is predictive of adverse cardiac events on long-term follow-up in moderate-risk patients undergoing major elective vascular surgery. Patients were enrolled prospectively between June 1997 and June 1999 at West Los Angeles VA and Harbor-UCLA Medical Centers. Adverse cardiac events were defined as congestive heart failure (CHF), myocardial infarction (MI), unstable angina (USA), and ventricular arrhythmias. Follow-up was obtained via clinic visits, telephone calls, and chart review. We studied 75 patients (76% male, 24% female) with a mean age of 65 years. Operative procedures were primarily femorodistal (83%) and aortic (16%). DTHAL/DMIBI results were normal in 35 patients (47%), demonstrated reversible ischemia in 26 (35%), and showed a fixed defect alone in 14 (18%). From the follow-up results of this study we conclude that there is no association between a reversible ischemia or an abnormal (fixed or reversible) DTHAL/DMIBI and adverse cardiac events or mortality on long-term follow-up in moderate-risk patients who have undergone major vascular surgery.

Cardiac response and complications during endovascular repair of abdominal aortic aneurysms: a concurrent comparison with open surgery

PURPOSE

The purpose of this study was to assess and to compare perioperative changes in left ventricular function and the incidence of adverse cardiac events in two groups of patients with abdominal aortic aneurysms, one during endovascular aneurysm repair (EAR) and the other during open aneurysm repair (OAR).

METHODS

One hundred twenty consecutive patients who underwent EAR (49 patients) or OAR (71 patients) were prospectively studied. During the operation, the left ventricular function was assessed by the recording of the left ventricle stroke work index (SWI) and the cardiac index (CI) with a pulmonary artery catheter. Measurements were performed before, during, and after stent-graft deployment or aortic cross-clamping. Both maneuvers were defined as aortic occlusion (AO). Transesophageal echocardiography was performed to identify signs of wall motion abnormalities of the left ventricular wall, which indicated myocardial ischemia. Six-lead electrocardiograph monitoring was maintained until discharge from the intensive care unit. Postoperative cardiac complications were diagnosed by clinical observation, 12-lead ECG analysis at 1, 3, and 7 days after the operation, transthoracic echocardiography at 1 month, and measurement of cardiac enzymes.

RESULTS

The two study groups were comparable with regard to most clinical aspects. The baseline myocardial performance was worse in patients who underwent EAR compared with patients who underwent OAR, as indicated by a reduced SWI (33.1 and 37.4, respectively; P =.03). During AO there was a comparable increase of the CI in both groups. However, after AO the rise in CI was higher in patients who underwent OAR compared with patients who underwent EAR (0.7 and 0.2, respectively; P <.01), representing a more pronounced hyperdynamic state. In addition, the SWI demonstrated a decrease in patients who underwent OAR compared with an increase in patients who underwent EAR during AO (-1.4 and +1.9, respectively; P =.04) and after AO (-0.9 and +2.6, respectively; P =.01). These findings represent more severe myocardial stress in patients who underwent OAR. The incidence of postoperative clinical cardiac adverse events was comparable in the two study groups. However, myocardial ischemia, as indicated by electrocardiography and transesophageal echocardiography, had a higher incidence in patients who underwent open surgery as compared with patients whose condition was managed endovascularly (57% and 33%, respectively; P =.01).

CONCLUSION

Hemodynamic alterations during endovascular repair were not as severe as those in patients with open surgery and indicated less myocardial stress in the former category. These findings may explain a lower incidence of myocardial ischemia that was observed during endovascular repair. A lower frequency of clinical perioperative cardiac events in patients undergoing endovascular treatment may ultimately be expected.

Dipyridamole-thallium/sestamibi before vascular surgery: a prospective blinded study in moderate-risk patients

PURPOSE

This study assessed in a prospective, blinded fashion whether a reversible defect on dipyridamole-thallium (DTHAL)/sestamibi (DMIBI) can predict adverse cardiac events after elective vascular surgery in patients with one or more clinical risk factors.

METHODS

Consecutive patients with one or more clinical risk factors underwent a preoperative blinded DTHAL/DMIBI. Patients with recent congestive heart failure (CHF) or myocardial infarction (MI) or severe or unstable angina were excluded.

RESULTS

Eighty patients (78% men; mean age, 65 years) completed the study. Diabetes mellitus was the most frequent clinical risk factor (73%), followed by age older than 70 years (41%), angina (29%), Q wave on electrocardiogram (26%), history of CHF (7%), and ventricular ectopy (3%). The results of DTHAL/DMIBI were normal in 36 patients (45%); a reversible plus or minus fixed defect was demonstrated in 28 patients (36%), and a fixed defect alone was demonstrated in 15 patients (19%). Nine adverse cardiac events (11%) occurred, including three cases of CHF, and one case each of unstable angina, Q wave MI, non-Q wave MI, and cardiac arrest (successfully resuscitated). Two cardiac deaths occurred (2% overall mortality), one after a Q wave MI and one after CHF and a non-Q wave MI. The cardiac event rate was 14% for reversible defect and 9.8% without reversible defect (P =.71). The cardiac event rate was 12.5% (one of eight cases) for two or more reversible defects, versus 11.1% (eight of 72 cases) for fewer than two reversible defects (P = 1.0). The sensitivity rate of two or more areas of redistribution was 11% (95% CI, 0.3%-48%), the specificity rate was 90%, and the positive and negative predictive values were 12.5% and 89%, respectively.

CONCLUSION

Our study demonstrated no association between reversible defects on DTHAL/DMIBI and adverse cardiac events in moderate-risk patients undergoing elective vascular surgery.

Negative impact of cardiac evaluation before vascular surgery

The optimal preoperative evaluation of cardiac risk in patients with peripheral vascular disease is controversial. In developing a paradigm for preoperative cardiac workup, potential adverse effects of evaluation and cardiac intervention must be considered. This study analyzed the deleterious outcomes of extensive, comprehensive cardiac evaluation and intervention before planned vascular surgery in patients treated at the Denver Department of Veterans Affairs Medical Center. Over a 12-month period between 1994 and 1995, 161 patients were scheduled to undergo major vascular operations; 153 patients came to operation. The decision to pursue a cardiac evaluation was variously made by a combination of surgeons, cardiologists, and anesthesiologists. No defined protocol was followed. Cardiac history, chest X-rays and ECGs were obtained for all patients. Extended cardiac evaluation included these studies plus special tests, including echocardiography (echo), radionuclide ventriculography (RNVG), dipyridamole thallium scintigraphy (DTS), and cardiac catheterization (CC). Extended cardiac evaluations were undertaken in 42 patients. Complications related to percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG) were also recorded. Cardiac mortality and morbidity after vascular interventions were itemized in all 153 patients. Forty-two male patients, aged 68 +/- 9 years, underwent extended cardiac evaluations before planned vascular operations. The median elapsed time for cardiac workup was 14 days (mean 30 +/- 59 days). The median and mean times from cardiac workup to vascular surgery were 25 days and 76 +/- 142 days, respectively. Eighteen (43%) patients had echo or RNVG; 22 (52%) patients had DTS; 27 (64%) had CC; 9 (21%) had PTCA; 7 (17%) had CABG. Sixteen (38%) patients had untoward events related to cardiac evaluation. Eight patients (19%: one with cerebrovascular disease, and seven with aortic aneurysms) refused vascular surgery after extended cardiac workup. Complications attributable to CC, PTCA, and CABG included prosthetic graft infection, pseudoaneurysms (two), sternal wound infections (two), renal failure and brain anoxia. Two patients with severe limb ischemia who were candidates for revascularization ultimately required amputations because of delay due to cardiac evaluations. Extensive cardiac evaluation prior to vascular operations can result in morbidity, delays, and refusal to undergo vascular surgery. The underlying indication for vascular operations and the local iatrogenic cardiac complication rates must be considered before ordering special studies.

Clinical evaluation of a new, point-of-care hemocytometer

OBJECTIVE

This study was designed to compare results obtained with a new point-of-care hemocytometer with those of two established (point-of-care and laboratory-based) instruments.

DESIGN

To compare CBC values between established laboratory-based and point-of-care instruments, measurements were performed on routinely obtained blood specimens for CBC analysis in our institutional laboratory (phase I) and on specimens from cardiac surgical patients before initiation of cardiopulmonary bypass and after discontinuation of cardiopulmonary bypass in phase II.

SETTING

Surgical and hospitalized patients at a tertiary care center.

PATIENTS

Measurements were obtained by using blood specimens obtained from 141 hospitalized patients from different services (phase I) or from a consecutive series of 204 patients undergoing cardiac operations (phase II).

MEASUREMENTS AND MAIN RESULTS

Hemoglobin (HGB), platelet count (PLT), red blood cell count, and white blood cell count (WBC) were measured with two on-site and one laboratory-based instruments. Hematocrit (HCT) was calculated by using measured variables. Linear regression demonstrated good correlations between Ichor and T540 HGB (r2 = .95), HCT (r2 = .95), PLT (r2 = .94), and WBC (r2 = .95) results (n = 408); similarly, good correlations were observed with Coulter STKS HGB (r2 = .92), HCT (r2 = .91), and PLT (r2 = .94) results (n = 141). The relationship between Ichor and Coulter STKS WBC (r2 = .27) was poor; however, when two Ichor-derived outlier values (>50) were excluded, the relationship was very good (r2 = .99). Bias analysis (mean +/- SD) demonstrated similar results between Ichor and T540 HGB (0.003+/-0.5), HCT (-0.21+/-1.5), WBC (0.79+/-1.3), and PLT values (-9.2+/-16.6) as well as STKS HGB (-0.08+/-0.7), HCT (-0.69+/-2.3), WBC (-0.62+/-5.8), and PLT values (-10.2+/-21.4).

CONCLUSIONS

The Ichor hemocytometer provides accurate hematologic results that can facilitate rapid quantitative assessment of CBC variables and thus may be clinically useful, especially in critically ill patients.

Prophylactic coronary artery revascularization for elective vascular surgery: study design. Veterans Affairs Cooperative Study Group on Coronary Artery Revascularization Prophylaxis for Elective Vascular Surgery

This article describes the design of an ongoing randomized trial intended to test whether patients who require elective vascular surgery would benefit from preoperative coronary artery revascularization prior to the vascular procedure. The primary objective is to determine whether coronary artery revascularization reduces long-term mortality (mean 3.5 years) in patients undergoing vascular surgery. The study design calls for 620 patients to be randomized and followed for a mean of 3.5 years following vascular surgery. Secondary endpoints include measures of quality of life and cost-effectiveness. Patients with coronary artery disease in need of an elective vascular operation are considered candidates for the study. Anatomic exclusion criteria include ejection fraction <20%, severe aortic stenosis (valve area <1.0 cm2), left main stenosis > or =50%, nonobstructive coronary artery disease (stenosis <70%), and coronary arteries that are not amenable to revascularization. Prior to the vascular surgery, the trial randomizes eligible patients to coronary artery revascularization (either bypass surgery or angioplasty) versus medical therapy. The trial stratifies the randomization by hospital and type of vascular surgery (intraabdominal versus infrainguinal) because of differences in long-term prognosis in those patients. A 1-year feasibility trial involving five Veterans Affairs (VA) medical centers of variable vascular surgical loads has been completed. The results showed that over 90% of expected patients could be randomized. As a result, a larger VA Cooperative Study involving 18 centers will begin recruitment of patients. The findings should help determine the best strategy for managing patients with coronary artery disease in need of elective vascular surgery.

The effects of recombinant human growth hormone on cardiopulmonary function in elective abdominal aortic aneurysm repair

OBJECTIVES

Cardiorespiratory complications are the predominant source of morbidity in patients undergoing major surgery. Recombinant human growth hormone (rhGH) has previously been shown to be effective in improving respiratory and cardiac function in compromised patients.

DESIGN

The aim of this study was to assess the effects of perioperative rhGH on cardiac function in 33 patients undergoing elective infrarenal abdominal aortic aneurysm repair.

METHODS

Patients were randomised to one of three groups: placebo for 6 days before and after surgery (control, n = 12); genotropin (GH) 0.3 units/kg/day for 6 days before and after surgery (pre and postop GH, n = 10) and placebo for 6 days before and GH (0.3 units/kg/day) for 6 days after surgery (postop EH, n = 11). Patients were assessed on days 7 and 1 before and days 7, 14 and 50 after operation. Intraoperative cardiac index (CI) was measured after induction of anaesthesia, before and after aortic cross-clamping, after aortic unclamping and at the end of surgery.

RESULTS

Pretreatment with GH resulted in a significantly higher heart rate during surgery and was associated with a trend towards higher cardiac index (CI) (p < 0.067) at all stages of surgery. Mean arterial blood pressure at the stage of aortic unclamping was significantly higher in patients treated with GH preoperatively.

CONCLUSIONS

Larger studies are required to evaluate the beneficial effects of GH in aortic surgery. However, data from this pilot study suggests that perioperative GH administration may result in improved cardiac performance during aortic surgery.

Perioperative cardiovascular morbidity in patients with coronary artery disease undergoing vascular surgery after percutaneous transluminal coronary angioplasty

OBJECTIVE

Patients with coronary artery disease (CAD) who undergo noncardiac surgery are at increased risk for perioperative myocardial infarction (PMI). Undergoing successful coronary artery bypass grafting (CABG) before such surgery has been shown to decrease perioperative cardiac morbidity and mortality. Percutaneous transluminal coronary angioplasty (PTCA) is an alternative treatment for these patients. Perioperative cardiac morbidity in patients with CAD who underwent PTCA before their vascular surgery was reviewed.

SETTING

A tertiary care referral center for patients with cardiovascular heart disease.

PARTICIPANTS

Review of vascular surgery database for patients who underwent vascular surgery preceded by PTCA between 1984 and 1995. Patients were excluded if they had a history of CABG within 2 years of surgery, had PTCA more than 18 months before surgery, or had incomplete data.

MEASUREMENTS

Data were collected concerning cardiac history, left ventricular (LV) function, perioperative cardiac morbidity (angina, MI, congestive heart failure [CHF], and arrhythmias).

MAIN RESULTS

Of 194 patients who underwent aortic abdominal surgery, carotid endarterectomy (CEA), or peripheral vascular surgery preceded by PTCA, 104 (54%) had a previous MI. Twenty-six patients (13.4%) had perioperative cardiac morbidity. Only one patient had an MI (0.5%; 95% confidence interval [CI], 0.0 to 2.8), whereas one patient died of CHF followed by multisystem organ failure (0.5%). The median interval between PTCA and surgery was 11 days (interquartile range, [IQR] 3 to 49 days). Patients who developed perioperative cardiac morbidity were older than those who did not (p = 0.02). Patients who had a history of CABG (before PTCA) had a higher incidence of postoperative angina (p = 0.04). The degree of preoperative LV dysfunction was linearly related to the incidence of new postoperative CHF (p = 0.01). Arrhythmias were more common in patients undergoing abdominal vascular surgery (17.9%) than in those undergoing CEA (2.5%; p = 0.03) or peripheral vascular surgery (5.2%; p = 0.02).

CONCLUSION

High-risk cardiac patients undergoing vascular surgery who have had PTCA performed up to 18 months preoperatively have a low incidence of perioperative cardiac morbidity. Prophylactic PTCA may be beneficial in patients with CAD who are at high risk for perioperative cardiac complications.

ST segment changes following retinal surgery

STUDY OBJECTIVE

To describe the perioperative cardiac morbidity in adult patients undergoing retinal surgery using continuous Holter monitoring.

DESIGN

Prospective study.

SETTING

University hospital.

PATIENTS

56 patients scheduled for elective retinal surgery with local anesthesia.

INTERVENTIONS

Patients were monitored continuously for 24 hours using a Holter recorder. Blood samples for creatine phosphokinase (CPK) and serum myocardial creatine phosphokinase (CPK-MB) were taken preoperatively and 24 hours postoperatively. The characteristics of myocardial ischemia were compared according to the number of risk factors for ischemic heart disease.

MEASUREMENTS AND MAIN RESULTS

The overall incidence of perioperative myocardial ischemia was high: 26.7% (n = 15). These patients exhibited 41 episodes of ischemia with mean ST segment change from baseline of 2.2+/-0.7 mm. However, almost all (93.3%) ischemic episodes were silent. Patients with two risk factors or more had 77% more episodes of ischemia than patients with one risk factor (p < 0.005), and the duration of ischemia was 47+/-22.5 minutes compared with 34.8+/-27.5 minutes (p = NS). The first episode of ischemia occurred an average of 10 hours after surgery. No patient had intraoperative evidence of ischemia. Half of the ischemic episodes were associated with an increase in heart rate. No patient had evidence of acute myocardial infarction.

CONCLUSION

Retinal surgery with local anesthesia is accompanied by a high incidence of postoperative myocardial ischemia. No negative outcome was correlated to the occurrence of postoperative myocardial ischemia. The significance of these findings has yet to be evaluated.

Safety of endovascular treatment in high-cardiac-risk patients with limb-threatening ischemia

Vascular surgery can be safely performed in approximately 60% of patients with advanced peripheral vascular disease, because of the high frequency of concomitant coronary artery disease and consequent increased risk of perioperative cardiac complications. The aim of this study was to validate the hypothesis that endovascular revascularization could be safely applied to high-cardiac-risk patients with a lower incidence of perioperative cardiac complications. One hundred and fourteen patients with peripheral vascular disease referred for revascularization underwent preoperatively a clinical and echocardiographic evaluation, at rest and under dipyridamole stress test, to assess the cardiac risk. Patients with high clinical score (according to Goldman and Detsky), or low left ventricular ejection fraction at rest, or positive dipyridamole stress test, were considered at high cardiac risk. To record adverse cardiac events, all patients were monitored during surgery, postoperatively, and followed up for 18 months after hospital discharge. Forty-eight patients (42%) were found to be at high cardiac risk. In this high-cardiac-risk group, endovascular surgery was performed in 37/48 patients (77%) (group A), while the remaining 11/48 patients (23%) were bypassed with open surgery (group B). Postoperative cardiac complications occurred in 16% of patients in group A and in 45% of patients in group B with two deaths (p < 0.05). At follow-up, 51% of patients in group A and 44% of patients in group B had suffered late cardiac events (p=ns), with 10 deaths in group A and three deaths in group B (p=ns). Limb salvage rate was similar in the two groups (95% group A, 100% group B; p=ns). These data show that high-cardiac-risk patients with limb-threatening ischemia have significantly less perioperative cardiac complications when treated by endovascular procedures instead of bypass surgery. Follow-up data on cardiac events confirm the severity of concomitant coronary artery disease in patients with peripheral vascular disease.

The influence of perioperative myocardial infarction on long-term prognosis following elective vascular surgery

STUDY OBJECTIVE

The present study was performed to determine the influence of a perioperative myocardial infarction on long-term mortality in patients who have undergone elective vascular surgery.

STUDY DESIGN

This was a 4-year follow-up of patients who had undergone elective vascular procedures at a Veterans Affairs Medical Center. Between January 1989 and December 1990, 115 consecutive patients underwent surgery for either an expanding abdominal aortic aneurysm (AAA) (38%) or for pain in the lower extremities (62%).

RESULTS

Vital status at 4 years postsurgery was determined for all patients. Thirty-day postoperative mortality was 3%, while estimates at 1, 2, 3, and 4 years were 19%, 26%, 35%, and 39%, respectively. Of the 45 patients who died within 4 years following surgery, the major causes of death were cardiac (40%), cancer (18%), cerebrovascular (13%), and peripheral vascular disease (11%). Univariate predictors of 1-year mortality on preoperative evaluation were an abnormal ECG, moderate or greater sized exercise thallium defect and left ventricular ejection fraction < or =40%, and a perioperative myocardial infarction. Univariate predictors of 4-year mortality were non-AAA surgery and diabetes mellitus. Perioperative myocardial infarction was a marginally significant independent predictor of 1-year mortality (p=0.06), while the need for non-AAA surgery was a strong independent predictor at 4 years.

CONCLUSIONS

Cardiac mortality is the major cause of late death among patients undergoing elective vascular surgery. Although preoperative indicators of symptomatic coronary artery disease and nonfatal perioperative myocardial infarction identified those individuals at increased mortality in the first postoperative year, the extent of vascular disease at presentation may be a more important determinant of long-term survival. A randomized trial in such patients is needed to assess the best strategy for treating patients with coexistent coronary artery and vascular diseases.

Should vein be saved for future operations? A 15-year review of infrainguinal bypasses and the subsequent need for autogenous vein

The decision to use prosthetic or autogenous vein as the initial conduit for first-time vascular bypass of the lower extremity depends in part on the likelihood of subsequent need for autogenous conduit for another leg or heart bypass. The true frequency of these later events is not known. To answer this question, we analyzed a database of infrainguinal and coronary artery bypasses (CABG) performed at one institution between January 1980 and July 1995, to determine how many patients required subsequent infrainguinal bypass or CABG after their initial leg bypass. Five hundred and seventy-two infrainguinal bypasses were performed on 440 patients (mean age 63.9); average follow-up was 5.6 years. The clinical philosophy favored autogenous vein for first bypass, which was used in 84% of first operations performed during the study period while prosthetic material was used in 16%. For patients in which vein was used for the first operation, and who went on to have a second operation, the use of prosthetic conduit rose from 16% of operations to 27% (p < 0.05). The rate of subsequent CABG after leg bypass was very low, 2% at 5 years, 3% at 10 years. The cumulative probability of requiring a subsequent infrainguinal bypass was 27% at 5 years, 32% at 10 years. Of these, 46% were ipsilateral and 54% were contralateral. Considering only subsequent tibial bypasses (where vein might be considered obligatory), the cumulative 5-year rate of subsequent leg bypass was only 13%. Another bypass was most likely to occur within the first 3 years, rarely thereafter. In summary, after primary infrainguinal bypass, additional procedures using vein may arise in 1/4 to 1/3 of patients, mostly in the first 3 years. However, only 13% will definitely need vein for tibial bypass in 5 years, and subsequent CABG is uncommon.

Effectiveness of pulmonary artery catheters in aortic surgery: a randomized trial

PURPOSE

To evaluate the routine use of pulmonary artery catheters (PAC) in patients who undergo aortic surgery.

METHODS

One hundred twenty patients were randomized to placement of PACs for perioperative monitoring and hemodynamic optimization (tune up) in the intensive care unit on the night before aortic operation, or to intravenous hydration in the ward and perioperative monitoring without PACs. Before randomization, all patients underwent routine adenosine thallium-201 scintigraphy.

RESULTS

To meet predetermined endpoints, 30 PAC patients (50%) received nitrates, inotropic agents, or both. PAC patients received more fluid in the preoperative period (p < 0.001) and in the first 24 hours after operation (p = 0.002) than control subjects. Eleven PAC patients (18%) and three control subjects (5%) had adverse intraoperative events (p = 0.02). There were 20 adverse postoperative events in 15 PAC patients (25%; nine cardiac, seven pulmonary, four acute tubular necrosis), which was not different compared with 11 postoperative events in 10 control subjects (17%; five cardiac, five pulmonary, one acute tubular necrosis). There were also no differences in duration of mechanical ventilation, intensive care unit stay, or hospital stay between groups. Postoperative cardiac complications were more common among patients who had a history of congestive heart failure (p = 0.02; odds ratio, 3.75; confidence interval, 1.3 to 11) or reperfusion defects on adenosine thallium scintigraphy (p = 0.01; odds ratio, 3.4; confidence interval, 1.2 to 9.4), regardless of group.

CONCLUSIONS

Routine use of PACs for perioperative monitoring with the above protocol during aortic surgery is not beneficial and may be associated with a higher rate of intraoperative complications. Preoperative tune up does not prevent postoperative cardiac, renal, and other complications. Variables such as cardiac risk factors and adenosine thallium scintigraphy may be more important predictors of cardiac events in patients who undergo aortic operations.

Vectorcardiographic changes as predictors of cardiac complications during major vascular surgery

OBJECTIVE

To elucidate the relation of changes in computerized vectorcardiographic trend parameters indicating perioperative myocardial ischemia with perioperative cardiac complications.

DESIGN

Prospective clinical study.

SETTING

A single university hospital.

PARTICIPANTS

Thirty-eight patients undergoing elective abdominal aortic surgery.

INTERVENTIONS

Computerized vectorcardiography recorded during surgery and for 48 hours postoperatively.

MEASUREMENTS AND MAIN RESULTS

Vectorcardiographic spatial alterations in the QRS complex (QRS-VD) and absolute (ST-VM) and spatial (STC-VM) ST-segment changes, previously used indicators of myocardial ischemia, were analyzed and related to the cardiac events detected clinically. In five patients with clearly ischemic (cardiac death, myocardial infarction, recurrent ischemia) and eight patients with possibly ischemic (congestive heart failure, arrhythmia) perioperative cardiac events, ST-VM and STC-VM were significantly increased intraoperatively. Postoperatively, these differences remained, but QRS-VD were also significantly increased. Intraoperative and postoperative changes indicating ischemia were strongly related (r = 0.83). The signs of ischemia were most pronounced during the postoperative 12 to 36 hours. The presence of 60 minutes of signs of ischemia during 2 hours revealed high sensitivity (85%), specificity (80%), and positive (69%) and negative (91%) predictive values for subsequent cardiac events. Traditional vector loop analysis showed signs of non-Q-wave infarctions in six patients, whereas only three of these were detected using standard clinical methods.

CONCLUSIONS

Vectorcardiographic signs of myocardial ischemia were significantly increased intraoperatively, but most pronounced postoperatively in the patients subsequently suffering cardiac events. The changes could be related to the individual cardiac morbidity with acceptable precision. Thus, continuous vectorcardiographic monitoring may be beneficial for patients at risk of developing perioperative ischemia.

The limits of generalized cardiac screening tests for predicting cardiac complications after infrainguinal arterial reconstruction

We examined the relative efficacies of different cardiac screening strategies for infrainguinal arterial bypass. The outcomes of 205 elective leg bypass procedures over a 10-year period, including myocardial infarction (MI), total cardiac complications, and mortality were tallied. Clinical risk factors popularized by Goldman and Eagle, and the results of dipyridamole thallium myocardial imaging (DThal) were recorded. The overall mortality rate was 3.4%, with a 3.4% incidence of MI and a 5.4% total cardiac complication rate. Both abnormal DThal (p = 0.011) and Goldman class II-IV (p = 0.030) were significant predictors of MI and cardiac death, but both suffered from poor specificity and positive predictive value. Because logistic regression analysis identified a correlation between angina, CHF, and an abnormal DThal, a customized screening strategy was developed to include the presence of angina, CHF and an abnormal DThal. Eighty-eight percent of patients suffering MI or death met these criteria, while only 11% of the complication-free group did. This screening strategy provided a superior sensitivity of 88%, specificity of 89%, positive predictive value of 25%, and 99% negative predictive value. A customized screening strategy (angina, CHF, abnormal DThal), developed from a 10-year experience with a single patient group, provided better predictive accuracy than any generalized screening formula.

Coronary bypass in vascular patients: a relatively high-risk procedure

A premise of cardiac risk stratification is that the added risk of coronary artery bypass grafting (CABG) is offset by the improved safety of subsequent vascular reconstruction (VR). We questioned if elective CABG is patients with severe peripheral vascular disease (PVD) is a relatively high-risk procedure. A cohort study of 680 elective CABG patients from January 1993 to December 1994 was performed using three mutually exclusive outcomes of complication-free survival, morbidity, and mortality. Patient characteristic, operative, and outcome data were prospectively collected. Retrospective review determined that 58 patients had either a standard indication for or a history of VR. Overall CABG mortality was 2.5%, with statistically similar but relatively higher rates for PVD as compared to non-PVD patients. In contrast, major morbidity occurred at rates 3.6-fold higher in PVD patients (39.7%) than in disease-free patients (16.7%) after adjustment for the effects of patient and operative variables (odds ratio [OR] 3.67, 95% confidence interval [CI] 1.93-6.99). CABG morbidity in the PVD patient was most likely in those patients with aortoiliac (OR 9.51, CI 3.20-28.27) and aortic aneurysmal (OR 5.24, CI 1.28-21.41) disease types. CABG in PVD patients is associated with significant major morbidity. Such morbidity may preclude or alter the timing of subsequent VR.

A prospective, randomized trial limiting perioperative red blood cell transfusions in vascular patients

BACKGROUND

Patients undergoing major arterial reconstruction have traditionally been transfused with red blood cells to keep hemoglobin concentrations above 10 g/dL in order to prevent anemia-induced myocardial ischemia. There are no data to support this practice. The hypothesis that vascular patients will tolerate a hemoglobin concentration of 9 g/dL was examined.

METHODS

Ninety-nine patients undergoing elective aortic and infrainguinal arterial reconstructions were prospectively randomized preoperatively to receive transfusions to maintain a hemoglobin level of either 10 g/dL or 9 g/dL.

RESULTS

Despite significantly different postoperative hemoglobin levels of 11.0 +/- 1.2 versus 9.8 +/- 1.3 g/dL (P <0.0001), there were no differences in mortality or cardiac morbidity rates or length of hospital stay. There were no differences in hemodynamic parameters. Oxygen delivery was lower in the group with lower hemoglobin levels, but there was no difference in O2 consumption between the groups.

CONCLUSIONS

A lower hemoglobin concentration was tolerated without adverse clinical outcome. Patients did not compensate for anemia by increased myocardial work, but by increasing O2 extraction in the peripheral tissues.

Effects of anesthetic technique on myocardial wall motion abnormalities during abdominal aortic surgery

OBJECTIVE

To assess the impact of regional supplemented general anesthesia (RSGEN) on regional myocardial function during abdominal aortic surgery (AAS).

DESIGN

Prospective randomized study.

SETTING

Single academic medical center.

PARTICIPANTS

Seventy-three patients scheduled for infrarenal aortic aneursymectomy.

INTERVENTIONS

Patients received standardized intraoperative anesthetic management consisting of either general anesthesia (GA; n = 37) or general anesthesia supplemented by epidural anesthesia (RSGEN; n = 36).

MEASUREMENTS AND MAIN RESULTS

Hemodynamic measurements and transesophageal echocardiograms (TEE) were obtained at eight intraoperative times. The electrocardiogram (ECG) was continuously recorded using Holter monitoring. Of the 56 patients with interpretable TEE recordings, 8 of 30 (27%) GA patients and 7 of 26 (27%) RSGEN patients developed new segmental wall motion abnormalities (SWMAs). There was no treatment effect on either the incidence (p = 0.23) or the intensity (p = 0.34) of SWMAs. Cross-clamping of the aorta was associated with the onset of new SWMAs (odds ratio, 8.2; 95% CI, 1.1 to 64; p = 0.04). Among the 63 patients with interpretable Holter recordings, 9 of 34 (26%) GA patients and 9 of 29 (31%) RSGEN patients exhibited intraoperative ischemia. There was no treatment effect on the incidence (p = 0.22) or intensity (p = 0.67) of ECG ischemia.

CONCLUSION

Despite providing modest hemodynamic depression, RSGEN did not reduce the incidence or intensity of either regional myocardial dysfunction or ECG ischemia. New SWMAs were temporally associated with cross-clamping of the aorta and tended to resolve with unclamping.

[Role of noninvasive examinations in the management of ischemic cardiopathy. V. Noninvasive examinations in the management of patients with chronic ischemic cardiopathy]

In the last few years the has been an enormous development in noninvasive testing in the field of clinical cardiology. In fact, excellent monographs on each one of these techniques have been published elsewhere, but fewer publications exist that treat the topic of their indications and use in an integrated way, except for in the most common clinical situations. In this paper, the treatment of patients who present chest pain, stable and unstable angina is discussed, including the study of postinfarction patients. Furthermore, the role of noninvasive tests in the detection of coronary heart disease in women and in patients with left bundle branch block is thoroughly analyzed; as well as their usefulness after surgical or percutaneous coronary revascularization and in patients with peripheral vascular disease.

Selective use of the intensive care unit after nonaortic arterial surgery

PURPOSE

The purpose of this study was to determine whether the institution of a clinical protocol combining 6 hours of recovery room observation and guidelines for intensive care unit (ICU) admission would allow selected patients to be safely transferred directly to a surgical floor after nonaortic arterial reconstruction.

METHODS

After a clinical pathway was formed, 134 consecutive patients undergoing 154 nonaortic arterial operations were prospectively enrolled in this study. Patients requiring ICU care and the responsible factors were identified. Comparisons of risk factors and demographics were made between those patients who did and did not require ICU care.

RESULTS

Twelve (7.8%) patients spent a total of 27 days in the ICU (range 1 to 11 days). As per our guidelines four patients were transferred to the ICU for invasive monitoring, and four were sent to the ICU because of refractory hemodynamic instability or arrhythmia in the postanesthetic recovery room. An additional four patients were transferred to the ICU after having been on the surgical floor for 24 to 72 hours because of the following perioperative complications: prolonged chest pain (one), pneumonia (one), heart failure (one), and graft occlusion requiring a urokinase infusion. Patients admitted to the ICU were more likely to have heart disease (p = 0.02) and to have had an operation other than carotid endarterectomy (p = 0.04) than those who were not. The 30-day mortality rate was 1.4%.

CONCLUSIONS

The implementation of a clinical protocol similar to the one used in this study will allow many patients undergoing nonaortic vascular surgery to avoid the use of the ICU. This approach will conserve hospital and financial resources without adversely affecting patient morbidity and mortality rates.

Evaluation of complete blood count results from a new, on-site hemocytometer compared with a laboratory-based hemocytometer

OBJECTIVE

To compare point-of-care results obtained from an on-site hemocytometer with values provided by an institutional laboratory instrument.

DESIGN

A prospective laboratory evaluation.

SETTING

The central laboratory and cardiac surgical intensive care unit of a university-affiliated tertiary care center.

PATIENTS

Normal range comparison was performed using blood specimens routinely obtained from 48 hospitalized patients for complete blood count analysis. The second evaluation was performed on blood specimens routinely obtained (in the intensive care unit) after cardiac surgery involving extracorporeal circulation in a series of 187 consecutive patients.

MEASUREMENTS AND MAIN RESULTS

Hemoglobin concentration, platelet count, mean corpuscular volume, mean platelet volume, and red and white blood cell counts were measured with both on-site (MD 16, Coulter Electronics, Hialeah, FL) and laboratory (STKS, Coulter Electronics) instruments. Hematocrit and red cell distribution width were calculated using measured variables. Blood specimens were obtained from two distinct patients series. To evaluate measurement values within the normal range, a series of 48 routinely obtained blood specimens for complete blood count analysis in our institutional laboratory were utilized for concurrent analysis with the on-site hemocytometer. To evaluate measurement values out of the normal range, a second comparison involved measurements performed on blood specimens obtained in the cardiac surgical intensive care unit for complete blood count analysis. Linear regression demonstrated good correlations between on-site and laboratory hemoglobin concentration (r2 = .97), hematocrit (r2 = .95), platelet count (r2 = .97), mean corpuscular volume (r2 = .91), red cell distribution width (r2 = .80), and red (r2 = .95) and white (r2 = .96) blood cell count results. A marginal correlation was observed between mean platelet volume values (r2 = .47). Bias analysis (mean +/- 2 SD) demonstrated similar measurements between on-site and laboratory hemoglobin concentration, hematocrit, platelet count, red blood cell count, white blood cell count, mean platelet volume, mean corpuscular volume, and red cell distribution width.

CONCLUSIONS

On-site hemoglobin concentration, hematocrit, white blood cell count, red blood cell count, red cell distribution width, and platelet count values compare well with those results obtained from the laboratory. The MD 16 hemocytometer (Coulter Electronics) provides on-site hematologic results that can provide an accurate and rapid quantitative assessment of platelets, and red and white blood cells. Rapid access to information obtained from this type of system may be clinically useful, especially in critically ill patients.

Cardiac evaluation of the diabetic patient prior to peripheral vascular surgery

The benefit of preoperative cardiac evaluation in the diabetic patient undergoing peripheral vascular surgery is uncertain. To investigate this issue we performed a retrospective review of 192 procedures performed in diabetic patients for chronic lower extremity arterial occlusive disease. The incidence of adverse postoperative cardiac events was determined, as well as its association with several preoperative factors including symptoms of coronary artery disease (CAD), extent and results of preoperative noninvasive cardiac evaluation, and operative site (aorta vs. lower extremity). The overall death and cardiac complication rates were 10.2% for lower extremity and 25.7% for aortic procedures (p = 0.02). For myocardial infarction and cardiac death alone, the rates were 5.1% and 5.7%, respectively (p > 0.10). Although a history of symptomatic CAD predicted the occurrence of any cardiac complication (28.3% vs. 8.2% [p < 0.01] for the aortic and lower extremity revascularization groups combined), no factor was found to be associated with the occurrence of myocardial infarction and cardiac death alone. In patients with a history of symptomatic CAD, there was no significant difference in the incidence of complications whether or not preoperative noninvasive cardiac testing was performed (28.1% vs. 28.6%, p > 0.10) or, if testing was performed, if the results were abnormal or normal (35.3% vs. 20.0%, p > 0.10). Similar results were obtained in patients with no history of symptomatic CAD. In summary, this retrospective review of our experience with noninvasive evaluation to detect CAD in diabetic patients undergoing peripheral vascular surgery failed to show any benefit in terms of reducing the incidence of postoperative cardiac events.

Development and validation of a Bayesian model for perioperative cardiac risk assessment in a cohort of 1,081 vascular surgical candidates

OBJECTIVES

This study sought to develop and validate a Bayesian risk prediction model for vascular surgery candidates.

BACKGROUND

Patients who require surgical treatment of peripheral vascular disease are at increased risk of perioperative cardiac morbidity and mortality. Existing prediction models tend to underestimate risk in vascular surgery candidates.

METHODS

The cohort comprised 1,081 consecutive vascular surgery candidates at five medical centers. Of these, 567 patients from two centers ("training" set) were used to develop the model, and 514 patients from three centers were used to validate it ("validation" set). Risk scores were developed using logistic regression for clinical variables: advanced age (>70 years), angina, history of myocardial infarction, diabetes mellitus, history of congestive heart failure and prior coronary revascularization. A second model was developed from dipyridamole-thallium predictors of myocardial infarction (i.e., fixed and reversible myocardial defects and ST changes). Model performance was assessed by comparing observed event rates with risk estimates and by performing receiver-operating characteristic curve (ROC) analysis.

RESULTS

The postoperative cardiac event rate was 8% for both sets. Prognostic accuracy (i.e., ROC area) was 74 +/- 3% (mean +/- SD) for the clinical and 81 +/- 3% for the clinical and dipyridamole-thallium models. Among the validation sets, areas were 74 +/- 9%, 72 +/- 7% and 76 +/- 5% for each center. Observed and estimated rates were comparable for both sets. By the clinical model, the observed rates were 3%, 8% and 18% for patients classified as low, moderate and high risk by clinical factors (p<0.0001). The addition of dipyridamole-thallium data reclassified >80% of the moderate risk patients into low (3%) and high (19%) risk categories (p<0.0001) but provided no stratification for patients classified as low or high risk according to the clinical model.

CONCLUSIONS

Simple clinical markers, weighted according to prognostic impact, will reliably stratify risk in vascular surgery candidates referred for dipyridamole-thallium testing, thus obviating the need for the more expensive testing. Our prediction model retains its prognostic accuracy when applied to the validation sets and can reliably estimate risk in this group.

Outpatient echocardiography as a predictor of perioperative cardiac morbidity after peripheral vascular surgical procedures

PURPOSE

A variety of preoperative provocative tests have been used to define the risk of cardiac morbidity and mortality after peripheral vascular procedures, including dipyridamole myocardial scintigraphy and dobutamine stress echocardiography. Although highly sensitive, these tests are time-consuming and associated with significant expense. We investigated outpatient echocardiography as a less resource-intensive means of assessing cardiac risk with operation.

METHODS

Over a 2-year period 250 consecutive patients underwent outpatient transthoracic echocardiography before elective peripheral vascular operation was performed. The accuracy of the Goldman, Detsky, and the American Society of Anesthesiologists' Physical Status Classification clinical indexes of cardiac risk were assessed with regard to the development of cardiac complications such as unstable angina, myocardial infarction, life-threatening ventricular arrhythmias, severe congestive heart failure, and cardiogenic shock. The accuracy of echocardiographically determined left ventricular ejection fraction was determined at threshold values between 20% and 60%.

RESULTS

Perioperative cardiac events developed in 23 (9.2%) of the patients, and nine (3.6%) of the patients died as a result of these complications. Clinical indexes lacked sensitivity in the preoperative prediction of cardiac complications. Receiver operating curve analysis defined a left ventricular ejection fraction of less than 50% as an appropriate threshold for defining patients at high risk, with a sensitivity of 78% and a specificity of 81% in the identification of patients who had cardiac morbidity. The positive predictive value was 27%, and the negative predictive value was 97%. The economic impact of outpatient echocardiography was well below that of dipyridamole myocardial scintigraphy or dobutamine stress echocardiography.

CONCLUSIONS

Outpatient echocardiography appears to offer a cost-efficient compromise between clinical criteria alone and provocative cardiac testing such as dipyridamole myocardial scintigraphy and dobutamine stress echocardiography in the preoperative screening of patients undergoing peripheral vascular surgical procedures.

Preoperative cardiac risk management

CAD is present in most patients with peripheral arterial disease and is the leading cause of morbidity and mortality after vascular operations. Clinical risk assessment attempts to identify those patients at low, intermediate, or high cardiac risk for adverse cardiac outcomes. Additional tests add little information to the estimates obtained by clinical scoring in patients at low risk. Patients with high cardiac risk scores are clearly at increased risk of experiencing postoperative complications, but further investigations are needed only if knowledge of the functional severity or degree of myocardial ischemia will alter subsequent management. In general, high-risk patients should proceed to coronary angiography, intensive perioperative monitoring, alteration in the planned operation, or avoidance of surgery altogether if indications are less than compelling. Those patients identified as intermediate risk by clinical scoring benefit most from additional tests. In these patients special studies or even coronary arteriography may be useful if the vascular surgery can be delayed until myocardial revascularization is completed. Practically, preoperative cardiac work-up must also consider the indication for surgery. Patients who have threatened limbs or ruptured aneurysms or are severely symptomatic cannot afford the time involved for obtaining additional tests. Moreover, the question of what to do with the information provided by special studies is problematic in these patients. For example, if significant symptomatic or asymptomatic CAD is present in a patient with a gangrenous foot, what is gained by the delay in lower extremity revascularization required when prophylactic CABG is performed? Reports supporting prophylactic CAD intervention are nonrandomized and uncontrolled. CABG and PTCA should be performed only on the merits of the patient's cardiac symptoms and coronary artery anatomy, not to enhance safety of the proposed vascular procedure, because advances in surgical and anesthetic techniques and intraoperative and postoperative monitoring have resulted in lower morbidity and mortality of elective vascular surgery.