Yehuda G. Wolf

Myocardial infarction after vascular surgery: the role of prolonged stress-induced, ST depression-type ischemia.

OBJECTIVESnThe goal of this study was to investigate the nature of the association between silent ischemia and postoperative myocardial infarction (PMI).nnnBACKGROUNDnSilent ischemia predicts cardiac morbidity and mortality in both ambulatory and postoperative patients. Whether silent stress-induced ischemia is merely a marker of extensive coronary artery disease or has a closer association with infarction has not been determined.nnnMETHODSnIn 185 consecutive patients undergoing vascular surgery, we correlated ischemia duration, as detected on a continuous 12-lead ST-trend monitoring during the period 48 h to 72 h after surgery, with cardiac troponin-I (cTn-I) measured in the first three postoperative days and with postoperative cardiac outcome. Postoperative myocardial infarction was defined as cTn-I >3.1 ng/ml accompanied by either typical symptoms or new ischemic electrocardiogram (ECG) findings.nnnRESULTSnDuring 11,132 patient-hours of monitoring, 38 patients (20.5%) had 66 transient ischemic events, all but one denoted by ST-segment depression. Twelve patients (6.5%) sustained PMI; one of those patients died. All infarctions were non-Q-wave and were detected by a rise in cTn-I during or immediately after prolonged, ST depression-type ischemia. The average duration ofischemia in patients with PMI was 226+/-164 min (range: 29 to 625), compared with 38+/-26 min (p = 0.0000) in 26 patients with ischemia but not infarction. Peak cTn-I strongly correlated with the longest, as well as cumulative, ischemia duration (r = 0.83 and r = 0.78, respectively). Ischemic ECG changes were completely reversible in all but one patient who had persistent new T wave inversion. All ischemic events culminating in PMI were preceded by an increase in heart rate (delta heart rate = 32+/-15 beats/min), and most (67%) of them began at the end of surgery and emergence from anesthesia.nnnCONCLUSIONSnProlonged, ST depression-type ischemia progresses to MI and is strongly associated with the majority of cardiac complications after vascular surgery.

Computed tomography scanning findings associated with rapid expansion of abdominal aortic aneurysms

PURPOSEnEarly repair of abdominal aortic aneurysms (AAA) is particularly appropriate for those that are most likely to expand. Our aim was to define features on computed tomography (CT) scanning associated with subsequent rapid aneurysm expansion.nnnMETHODSnWe reviewed CT scans of 80 patients with AAA (> 3.0 cm) who underwent CT scanning of the abdomen and pelvis two times, at least 6 months apart, between 1986 and 1992. The aneurysms initially measured 4.4 +/- 0.6 cm, and the mean interval between obtaining scans was 22 +/- 12 months. Clinical variables assessed included age, sex, medical risk factors, underlying cardiovascular and pulmonary diseases, and administration of beta blockers and lipid-lowering agents. Computer-aided measurements on each CT scan section included the maximal and minimal diameters and area of the aneurysm. Dimensions of the luminal thrombus and the arc of aneurysm wall covered by thrombus (TARC). Maximal aneurysm dimensions were related to juxtarenal aortic and second lumbar vertebral body dimensions.nnnRESULTSnMean aneurysm expansion was 0.26 +/- 0.25 cm/yr. CT scanning variables that correlated significantly with rate of expansion included the mean TARC (r = 0.43, p < 0.001), thrombus volume fraction (r = 0.37, p < 0.001), TARC on the largest aneurysm cross section (r = 0.34, p < 0.01), and thrombus area fraction (r = 0.30, p < 0.01). Rapid expansion (> 0.5 cm/yr) occurred in 15 (19%) aneurysms. The two predictors for rapid expansion on logistic regression analysis were mean TARC (p < 0.005) and the presence of carotid artery disease (p < 0.05).nnnCONCLUSIONnAn increased AAA thrombus load is associated with a higher likelihood of rapid expansion and should weigh in favor of early surgical repair.

Perioperative myocardial ischemia and infarction: identification by continuous 12-lead electrocardiogram with online ST-segment monitoring.

Background Perioperative myocardial ischemia is conventionally monitored using five electrocardiographic leads, with only one precordial lead placed at V5. This is based on studies from more than a decade ago. The authors reassessed this convention by analyzing data obtained from continuous on-line 12-lead electrocardiographic monitoring. Methods One hundred eighty-five consecutive patients undergoing vascular surgery were monitored by continuous 12-lead ST-trend analysis during and for 48–72 h after surgery. Cardiac troponin I was measured in the first 3 postoperative days, and cardiac outcome was prospectively recorded. Ischemia was defined as ST deviation, relative to the reference preanesthesia electrocardiogram, of 0.2 mV or more in one lead or 0.1 mV or more in two contiguous leads, lasting more than 10 min. Results During 11,132 patient-hours of monitoring, 38 patients (20.5%) had 66 transient ischemic events, with all but one denoted by ST-segment depression. Twelve patients (6.5%) sustained postoperative infarction (cardiac troponin I > 3.1 ng/ml). Among the 38 patients with ischemia, lead V3 most frequently (86.8%) demonstrated ischemia, followed by V4 (78.9%) and V5 (65.8%). Among the 12 patients with infarction, V4 was most sensitive to ischemia (83.3%), followed by V3 and V5 (75% each). Combining two precordial leads increased the sensitivity for detecting ischemia (97.4% for V3 + V5 and 92.1% for either V4 + V5 or V3 + V4) and infarction (100% for V4 + V5 or V3 + V5 and 83.3% for V3 + V4). On average, baseline preanesthesia ST was above isoelectric in V1 through V3 and below isoelectric in V5 through V6. Lead V4 was closest to the isoelectric level on the baseline electrocardiogram, rendering it most suitable for ischemia monitoring. Conclusions As a single lead, V4 is more sensitive and appropriate than V5 for detecting prolonged postoperative ischemia and infarction. Two precordial leads or more are necessary so as to approach a sensitivity of greater than 95% for detection of perioperative ischemia and infarction.

Screening for abdominal aortic aneurysms during lower extremity arterial evaluation in the vascular laboratory

PURPOSEnThe purpose of this study was to evaluate the cost-effectiveness of screening for abdominal aortic aneurysms (AAA) during noninvasive lower extremity arterial examination in the vascular laboratory.nnnMETHODSnOver 30 months we screened 531 patients who underwent lower extremity arterial evaluations in the vascular laboratory. The patients had fasted overnight, and, after the regular noninvasive lower extremity arterial examination, the abdominal aorta was screened with B-mode ultrasonography.nnnRESULTSnThe aorta was adequately visualized in 475 patients (89%). Mean aortic diameter was 19.6 +/- 4.1 mm at the juxtarenal level and 18.8 +/- 7.2 mm in the lower infrarenal aorta. The aortic diameter was larger in men (p < 0.001) and in smokers (p < 0.001). AAA (diameter greater than 3.0 cm) were identified in 32 patients (6.0% of the 531 patients screened), and 15 of the aneurysms were equal to or larger than 4.0 cm. The best predictors for AAA by logistic regression analysis were male sex (p < 0.005), advanced age (greater than 65 years, p < 0.01), and a history of smoking (p < 0.01). The prevalence of AAA was 6.7% (32/475) in the population in whom the aorta was visualized and 15.2% (19/125) in male smokers over 65 years of age. Aneurysms of 4.0 cm or greater were identified in 3.2% of the entire population screened and 8.8% of male smokers over age 65. Limited aortic scanning prolonged the vascular laboratory examination by an average of 5 minutes. Thus detection of one aneurysm required 83 minutes of scanning time for the whole population studied and 36 minutes of scanning of male smokers over age 65, at a cost of

Infection of a ruptured aortic aneurysm and an aortic graft with bacille Calmette-Guérin after intravesical administration for bladder cancer ☆ ☆☆ ★

240 to

High Rate of Candidemia in Patients Sustaining Injuries in a Bomb Blast at a Marketplace: A Possible Environmental Source

553 per aneurysm identified.nnnCONCLUSIONnScreening for AAA during lower extremity arterial evaluation in the vascular laboratory addresses a high-risk population, is cost-effective, and should be considered an appropriate and valuable addition to the examination protocol.

Results of reconstruction in major pelvic and extremity venous injuries.

A case of aortic graft infection with bacille Calmette-Guérin (BCG) is described. The graft was placed during urgent repair of a ruptured abdominal aortic aneurysm 2 years after intravesical administration of BCG for grade II transitional cell carcinoma of the bladder with associated carcinoma in situ. At the time of operation, no gross evidence of infection was found and pathologic examination of the aortic wall was unremarkable. Aortic graft infection with BCG was diagnosed 1 year after placement of the graft. Retrospective examination of formalin-fixed, paraffin-embedded aortic wall and thrombus removed at the time of graft placement by the polymerase chain reaction technique demonstrated the presence of mycobacterial DNA. The patients condition improved with medical therapy during an observation period of 18 months with near total resolution on computed tomography scanning. Ultimately (20 months later), an aortoenteric fistula developed that required graft removal and axillobifemoral bypass.

Predictive factors for limb occlusions after endovascular aneurysm repair

In this study, a cluster of candidemia among patients sustaining injuries in a bomb blast at a marketplace was investigated by means of a multivariate analysis, a case-control study, and quantitative air sampling. Candidemia occurred in 7 (30%) of 21 patients (58% of those admitted to the intensive care unit [ICU]) between 4 and 16 days (mean, 12 days) after the injury and was the single most frequent cause of bloodstream infections. Inhalation injury was the strongest predictor for candidemia by multivariate analysis. Candidemia among the case patients occurred at a significantly higher rate than among comparable trauma patients injured in different urban settings, including a pedestrian mall (2 of 29; P=. 02), and among contemporary ICU control patients (1 of 40; P=.001). Air sampling revealed exclusive detection of Candida species and increased mold concentration in the market in comparison with the mall environment. These findings suggest a role for an exogenous, environmental source in the development of candidemia in some trauma patients.

Nitroglycerin decreases medial smooth muscle cell proliferation after arterial balloon injury

PURPOSEnOutcome and venous patency after reconstruction in major pelvic and extremity venous injuries was studied.nnnMETHODSnWe retrospectively reviewed 46 patients with 47 venous injuries.nnnRESULTSnInjuries were caused by penetrating trauma in 37 extremities, blunt trauma in 6 patients, and were iatrogenic in 4 patients. Pelvic veins were injured in 4 patients, lower-extremity veins were injured in 39 limbs in 38 patients, and upper-extremity veins were injured in 4 patients. Concomitant arterial injuries occurred in 37 patients. Venous repairs were mostly of the complex type and included spiral or panel grafts in 15 (32%) reconstructions, interposition grafts or patch venoplasty in 19 (40%) reconstructions, end-to-end and lateral repair in 11 patients, and ligation in 2 patients. Two patients underwent early amputation. Early transient limb edema occurred in 2 patients, and postoperative venous occlusions were documented in 4 patients. Full function was regained in 39 (81%) extremities. No variable, including 4 retrospectively applied extremity injury scores (mangled extremity severity score [MESS], limb salvage index [LSI], mangled extremity syndrome index [MESI], predictive salvage index [PSI]), correlated with outcome. High values on all 4 scores were significantly associated with reexplorations (P <.02), which were done in 8 patients for debridement (5), arrest of bleeding (2), and repair of a missed arterial injury (1). Follow-up of 28 +/- 6 months on 27 patients (57%; duplex scan in 18, continuous-wave Doppler and plethysmography in 9, and venography in 3) showed 1 occlusion 6 weeks after the injury and patency of all other venous reconstructions.nnnCONCLUSIONnReconstructions of major venous injuries with a high rate of complex repairs result in a large proportion of fully functional limbs and a high patency rate. A high extremity injury score predicts the need for reexploration of the extremity. Mostocclusions occur within weeks of injury, and the subsequent delayed occlusion rate is very low.

Mesenteric bypass for chronic mesenteric ischaemia

OBJECTIVEnGreater flexibility and smaller sizes for introducer sheaths in the newest stent grafts increase the feasibility of endovascular aneurysm repair but raise concerns about long-term limb patency. The aim of the study was to determine the incidence of and predictive factors for limb occlusion after use of the Endurant stent graft (Medtronic Inc, Minneapolis, Minn) for abdominal aortic aneurysm.nnnMETHODSnThe Endurant Stent Graft Natural Selection Global Postmarket Registry (ENGAGE) prospectively included 1143 patients treated with bifurcated devices who were observed for up to 2 years. Limb occlusions were evidenced by computed tomography, angiography, or ultrasound. To predict stent graft limb occlusion, a two-step model-building technique was applied. We first identified predictors from a total of 47 covariates obtained at baseline and in the periprocedural period. Subsequently, we reduced the set of potential predictors to key factors that are clinically meaningful. To handle large numbers of covariates, we used the Classification And Regression Tree (CART) method.nnnRESULTSnForty-two stent graft limbs occluded in 39 patients (3.4% of the patients). At 2 years, the rate of freedom from stent graft limb occlusion calculated by Kaplan-Meier plot was 97.9% (standard error [SE], 0.33%). Of the 42 occlusions, 13 (31%) were observed within 30 days and 30 (71%) within 6 months. The strongest independent predictors were distal landing zone on the external iliac artery, external iliac artery diameter ≤10 mm, and kinking. High-risk vs low-risk patients were identified according to a decision tree based on the strongest predictors. Freedom from stent graft limb occlusion was 96.1% (SE, 0.64%) in high-risk patients vs 99.6% (SE, 0.19%) in low-risk patients.nnnCONCLUSIONSnAfter Endurant stent grafting, the incidence of limb occlusion was low. Classifying patients as high risk vs low risk according to the algorithm used in this study may help define specific strategies to prevent limb occlusion and improve the overall results of endovascular aneurysm repair using the latest generation of stent grafts.