Accuracy of stress Tc-99m tetrofosmin myocardial perfusion tomography for the diagnosis and localization of coronary artery disease in women

BACKGROUND

Earlier studies have suggested a modest accuracy of stress thallium 201 myocardial perfusion imaging (MPI) for the diagnosis of coronary artery disease (CAD) in women. The accuracy of stress MPI with technetium 99m tetrofosmin has not been studied in women. The aim of this study was to assess the accuracy of stress Tc-99m tetrofosmin MPI for the diagnosis and localization of CAD in women.

METHODS AND RESULTS

We studied 88 women who underwent exercise or dobutamine stress Tc-99m tetrofosmin tomography and coronary angiography within 3 months. Significant CAD was defined as a stenosis 50% or greater in diameter in at least 1 major epicardial coronary artery. Myocardial perfusion abnormalities were detected in 44 of 53 patients with significant CAD and in 7 of 35 patients without significant CAD (overall sensitivity, 83% [95% confidence interval (CI), 73%-93%]; specificity, 80% [95% CI, 67%-93%]; and accuracy, 82% [95% CI, 74%-90%]). The sensitivity was 72% (18/25) in patients with single-vessel CAD and 93% (26/28) in patients with multivessel CAD. Perfusion abnormalities were detected in 2 or more vascular distributions in 20 of 28 patients with multivessel CAD and in 4 of 60 patients without multivessel CAD (sensitivity for the identification of multivessel CAD, 71% [95% CI, 55%-88%]; specificity, 93% [95% CI, 86%-98%]; and accuracy, 86% [95% CI, 79%-93%]). The sensitivity, specificity, and accuracy were 82%, 84%, and 83%, respectively, for the diagnosis of CAD in the left anterior descending artery; 77%, 84%, and 81%, respectively, for CAD in the right coronary artery; and 74%, 80%, and 78%, respectively, for CAD in the left circumflex artery.

CONCLUSION

Stress Tc-99m tetrofosmin MPI is an accurate noninvasive technique for the diagnosis and localization of CAD in women.

Prognostic role of dobutamine stress echocardiography in myocardial viability

PURPOSE OF REVIEW

The aim of this review is to provide a perspective on the role of dobutamine stress echocardiography to evaluate myocardial viability and assess prognosis in patients with ischemic left ventricular dysfunction.

RECENT FINDINGS

Pooled analysis of currently available data demonstrates that dobutamine stress echocardiography provides useful information on recovery of dysfunctional but viable myocardium and prognosis. In fact, improvement of long-term prognosis may be the ultimate clinical challenge in the management of patients with ischemic left ventricular dysfunction. Dobutamine stress echocardiography can be used to assess residual ischemia and contractile reserve, which are significant determinants of prognosis. Additionally, other echocardiographic variables, such as end-diastolic wall thickness, end-systolic volume, and extent of viability, affect outcome after revascularization in patients with ischemic cardiomyopathy.

SUMMARY

Dobutamine stress echocardiography provides information on myocardial ischemia, contractile reserve, and other prognostically relevant parameters in patients with ischemic left ventricular dysfunction. This information can be used to select the optimal treatment strategy for these patients and to estimate and improve clinical outcome.

The influence of aneurysm size on perioperative cardiac outcome in elective open infrarenal aortic aneurysm repair

BACKGROUND

Abdominal aortic aneurysm (AAA) size and growth has been found to be associated with local generation of inflammation markers such as interleukin-6. Inflammation also seems to be important in perioperative adverse cardiac events. We hypothesized that patients with a large AAA are at increased risk for cardiac events.

METHODS

Consecutive patients who underwent a computed tomography angiography scan before open elective infrarenal AAA repair between March 2000 and December 2005 at three hospitals were analyzed. All patients were screened for the clinical risk factors of age, gender, angina pectoris, myocardial infarction, heart failure, diabetes, stroke, renal failure, and chronic obstructive pulmonary disease, as well as for cardioprotective medication. Postoperative data on troponin release, creatine kinase/creatine kinase isoenzyme MB, and electrocardiogram were routinely collected on days 1, 3, 7, and 30. The main outcome measure was the combined end point of 30-day cardiovascular death and nonfatal myocardial infarction. Multivariate Cox regression analysis was used to evaluate the influence of AAA size on postoperative cardiac outcome.

RESULTS

The study included 500 patients. Their mean age was 69.8 +/- 9.5 years, and 431 (86%) were men. Thirty-one patients (6.2%) had perioperative cardiovascular complications, consisting of 15 (3.0%) cardiovascular deaths and 16 (3.2%) nonfatal myocardial infarctions. After correction for other risk factors, including age, Revised Cardiac Risk Index, medication use, duration of surgery, and intraoperative blood loss, AAA size was independently associated with perioperative nonfatal myocardial infarction and cardiovascular death (3.2% increase in risk for each millimeter added, 95% confidence interval 1.1% to 6.2%, P = .007).

CONCLUSION

A larger AAA size is independently associated with an increased incidence of perioperative cardiovascular complications after elective infrarenal AAA repair.

Prognostic value of exercise stress technetium-99m-tetrofosmin myocardial perfusion imaging in patients with normal baseline electrocardiograms

Exercise stress electrocardiography is the recommended method for cardiac evaluation of patients with normal electrocardiograms (ECGs). There are no data to indicate an independent value of myocardial perfusion imaging (MPI) in predicting mortality in these patients. This study assessed the value of exercise stress MPI in predicting mortality in patients with normal baseline ECGs. We studied 319 patients (55 +/- 10 years of age; 180 men) with normal ECGs by exercise stress technetium-99m tetrofosmin MPI. End points during follow-up were cardiac and all-cause mortalities and hard cardiac events. A normal scan was detected in 190 patients (60%). Myocardial perfusion abnormalities were fixed in 59 patients (18%) and reversible in 70 (23%). During a mean follow-up of 7 +/- 1.2 years, 46 patients (14%) died. Death was considered cardiac in 28 patients (9%). Nonfatal myocardial infarction occurred in 12 patients (4%). Annual cardiac death rates were 0.4% in patients with normal perfusion, and 2.7% in patients with reversible defects. Annual total mortality rates were 1.1% in patients with normal perfusion and 3.4% in patients with reversible defects. In a multivariate analysis model, reversible perfusion abnormalities were associated with cardiac death (RR 2.8, 95% confidence interval 1.6 to 5.1) and hard cardiac events (RR 2.7, 95% confidence interval 1.5 to 4.5). Perfusion abnormalities in multivessel distribution were predictive of all-cause mortality (RR 2, 95% confidence interval 1.4 to 3.2). ST-segment depression was not significantly associated with events. In conclusion, stress technetium-99m tetrofosmin MPI provides independent information for predicting cardiac and overall mortalities in patients with normal ECGs. Reversible perfusion abnormalities, but not ischemic electrocardiographic changes, are predictive of outcome in these patients.

Should Major Vascular Surgery Be Delayed Because of Preoperative Cardiac Testing in Intermediate-Risk Patients Receiving Beta-Blocker Therapy With Tight Heart Rate Control?

OBJECTIVES

The purpose of this study was to assess the value of preoperative cardiac testing in intermediate-risk patients receiving beta-blocker therapy with tight heart rate (HR) control scheduled for major vascular surgery.

BACKGROUND

Treatment guidelines of the American College of Cardiology/American Heart Association recommend cardiac testing in these patients to identify subjects at increased risk. This policy delays surgery, even though test results might be redundant and beta-blockers with tight HR control provide sufficient myocardial protection. Furthermore, the benefit of revascularization in high-risk patients is ill-defined.

METHODS

All 1,476 screened patients were stratified into low-risk (0 risk factors), intermediate-risk (1 to 2 risk factors), and high-risk (> or =3 risk factors). All patients received beta-blockers. The 770 intermediate-risk patients were randomly assigned to cardiac stress-testing (n = 386) or no testing. Test results influenced management. In patients with ischemia, physicians aimed to control HR below the ischemic threshold. Those with extensive stress-induced ischemia were considered for revascularization. The primary end point was cardiac death or myocardial infarction at 30-days after surgery.

RESULTS

Testing showed no ischemia in 287 patients (74%); limited ischemia in 65 patients (17%), and extensive ischemia in 34 patients (8.8%). Of 34 patients with extensive ischemia, revascularization before surgery was feasible in 12 patients (35%). Patients assigned to no testing had similar incidence of the primary end point as those assigned to testing (1.8% vs. 2.3%; odds ratio [OR] 0.78; 95% confidence interval [CI] 0.28 to 2.1; p = 0.62). The strategy of no testing brought surgery almost 3 weeks forward. Regardless of allocated strategy, patients with a HR <65 beats/min had lower risk than the remaining patients (1.3% vs. 5.2%; OR 0.24; 95% CI 0.09 to 0.66; p = 0.003).

CONCLUSIONS

Cardiac testing can safely be omitted in intermediate-risk patients, provided that beta-blockers aiming at tight HR control are prescribed.

Plasma natriuretic peptide levels reflect changes in heart failure symptoms, left ventricular size and function after surgical mitral valve repair

BACKGROUND AND AIM

N-terminal pro-B-type natriuretic peptide (NT-proBNP) has diagnostic and prognostic value in patients with heart failure. The present prospective study was designed to assess whether changes in NT-proBNP levels after surgical mitral valve repair reflect changes in heart failure symptoms and changes in left atrial size, left ventricular size and left ventricular function.

METHODS

The study population consisted of 22 patients (mean age: 62.8 +/- 14.2 years, 68% male) undergoing surgical mitral valve repair. Serial NT-proBNP measurements, transthoracic echocardiography and New York Heart Association (NYHA) class assessment were performed before and 6 months after surgery.

RESULTS

All patients underwent successful mitral valve repair and no patients died during follow-up. The decrease in NT-proBNP level was associated with the reduction in left atrial dimension (r = 0.72, P < 0.001), left ventricular end-systolic dimension (r = 0.63, P = 0.002), left ventricular end-diastolic dimension (r = 0.46, P = 0.031), and the increase in fractional shortening (r = - 0.63, P = 0.002). Finally, patients with decreasing NT-proBNP levels revealed a significant improvement in heart failure symptoms (NYHA class).

CONCLUSION

Changes in NT-proBNP after surgical mitral valve repair reflect changes in heart failure symptoms and changes in left atrial and ventricular dimensions and function.

Plasma N-terminal pro-B-type natriuretic peptide as long-term prognostic marker after major vascular surgery

OBJECTIVE

To assess the long-term prognostic value of plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) after major vascular surgery.

DESIGN

A single-centre prospective cohort study.

PATIENTS

335 patients who underwent abdominal aortic aneurysm repair or lower extremity bypass surgery.

INTERVENTIONS

Prior to surgery, baseline NT-proBNP level was measured. Patients were also evaluated for cardiac risk factors according to the Revised Cardiac Risk Index. Dobutamine stress echocardiography (DSE) was performed to detect stress-induced myocardial ischaemia.

MAIN OUTCOME MEASURES

The prognostic value of NT-proBNP was evaluated for the endpoints all-cause mortality and major adverse cardiac events (MACE) during long-term follow-up.

RESULTS

In this patient cohort (mean age: 62 years, 76% male), median NT-proBNP level was 186 ng/l (interquartile range: 65-444 ng/l). During a mean follow-up of 14 (SD 6) months, 49 patients (15%) died and 50 (15%) experienced a MACE. Using receiver operating characteristic curve analysis for 6-month mortality and MACE, NT-proBNP had the greatest area under the curve compared with cardiac risk score and DSE. In addition, an NT-proBNP level of 319 ng/l was identified as the optimal cut-off value to predict 6-month mortality and MACE. After adjustment for age, cardiac risk score, DSE results and cardioprotective medication, NT-proBNP > or =319 ng/l was associated with a hazard ratio of 4.0 for all-cause mortality (95% CI: 1.8 to 8.9) and with a hazard ratio of 10.9 for MACE (95% CI: 4.1 to 27.9).

CONCLUSION

Preoperative NT-proBNP level is a strong predictor of long-term mortality and major adverse cardiac events after major non-cardiac vascular surgery.

Outcome after redo coronary artery bypass grafting in patients with ischaemic cardiomyopathy and viable myocardium

BACKGROUND

Repeat coronary artery bypass grafting (redo-CABG) in patients with ischaemic cardiomyopathy is associated with high perioperative risk and worse long-term outcome compared with patients undergoing their first CABG.

OBJECTIVE

To assess whether patients with viable myocardium undergoing redo-CABG have a better outcome.

METHODS

18 patients with ischaemic cardiomyopathy underwent redo-CABG and 34 underwent their first CABG; all had substantial viability (> or =25% of the left ventricle) on dobutamine stress echocardiography (DSE). Left ventricular ejection fraction (LVEF) and heart failure symptoms were assessed before and 9-12 months after revascularisation. Cardiac event rate was assessed during the follow-up period (median 4 years, 25-75th centile 2.8-4.9 years).

RESULTS

The extent of viable myocardium on DSE was comparable in the two groups (11.3 (3.9) segments in patients who underwent redo-CABG v 12.8 (3.0) in patients who underwent their first CABG; p = NS). LVEF improved from 32% (9%) to 39% (12%); p = 0.01, in patients who underwent redo-CABG and from 30% (7%) to 36% (7%); p<0.01, in those who underwent their first CABG; New York Heart Association class improved from 2.5 (1.1) to 1.9 (0.8); p = 0.03, and from 2.7 (1.0) to 1.8 (0.70); p<0.01, respectively. In patients who underwent redo-CABG, the perioperative mortality was 0, post-surgery inotropic support was needed in 11% of the patients and mid-term (4-year) survival was 100%, with a total event rate of 28%. All these variables were not statistically different from patients who underwent their first CABG (p = 0.50, 0.90, 0.08 and 0.81, respectively).

CONCLUSION

Patients with ischaemic cardiomyopathy and substantial viability undergoing redo-CABG benefit from revascularisation in terms of improvement in LVEF, heart failure symptoms, angina and mid-term prognosis.

Hemodynamic responses and long-term follow-up results in patients using chronic beta 1-selective and nonselective beta-blockers during dobutamine stress echocardiography

OBJECTIVE

This study was undertaken to determine to what extent hemodynamic responses to dobutamine infusion between patients using concomitant beta1-selective or nonselective beta-blockers differ and whether this difference affects the long-term prognostic value of dobutamine stress echocardiography with respect to cardiac events.

DESIGN

Single center, observational study.

METHODS

A total of 1234 patients using chronic beta-blockers underwent dobutamine stress echocardiography and were prospectively included in the study. Heart rate and blood pressure responses were measured during the dobutamine stress echocardiography protocol. During a median follow-up time of 4 years (range: 0.5-14 years), overall and cardiac mortality and nonfatal myocardial infarction were noted.

RESULTS

A total of 954 and 280 patients were using beta1-selective and nonselective beta-blockers, respectively. During dobutamine stress echocardiography, the heart rate response was significantly higher, systolic and diastolic blood pressure responses were significantly lower and the double product of heart rate and systolic blood pressure was similar in patients using beta1-selective than in patients using nonselective beta-blockers. In patients with and without new wall motion abnormalities during dobutamine stress echocardiography, a similar cardiac event-free survival was observed irrespective of the selectivity of beta-blockers (P=0.9 and 0.3, respectively).

CONCLUSION

During dobutamine stress echocardiography, heart rate and blood pressure response was different, but the double product was similar in patients using beta1-selective or nonselective beta-blockers, which may explain why the long-term prognostic value of dobutamine stress echocardiography is similar in these two groups.

Rise and fall of B-type natriuretic peptide levels in patients with coronary artery disease and normal left ventricular function after cardiac revascularization

BACKGROUND

Recently, it was shown that B-type natriuretic peptide levels are increased in patients with acute coronary syndromes.

AIMS

To assess the relation between B-type natriuretic peptide and ischemia in patients with stable and unstable angina pectoris with normal left ventricular function in relation to the extent of ischemia and response to revascularization.

METHODS

Fifty-nine consecutive patients were enrolled in the study, patients were divided into two groups: stable angina patients (group I, n=18), and unstable coronary patients (group II, n=41). Baseline characteristics were compared with 15 age-matched and sex-matched participants. B-type natriuretic peptide levels were measured at baseline and 3, 7 and 90 days after coronary revascularization in group I and II.

RESULTS

Patients with unstable angina pectoris had increased B-type natriuretic peptide levels compared with stable angina pectoris patients (B-type natriuretic peptide levels: controls 15.5+/-13 pg/ml, stable angina pectoris group 28.4+/-19 pg/ml, unstable angina pectoris group 104+/-81 pg/ml; P<0.01). A relationship between the number of affected coronary vessels and B-type natriuretic peptide was assessed (one-vessel 29.9+/-21 pg/ml, two-vessel 93.8+/-87 pg/ml, three-vessel 119+/-88 pg/ml; P<0.01). After revascularization, B-type natriuretic peptide levels decreased in groups I and II (25+/-20 vs. 39+/-28 pg/ml) and were similar after 90 days in percutaneous transluminal coronary angiograghy and in coronary artery bypass grafting groups (percutaneous transluminal coronary angiography 26+/-22 pg/ml, coronary artery bypass grafting 36+/-26 pg/ml; NS).

CONCLUSIONS

B-type natriuretic peptide levels increase in unstable angina pectoris patients and are linked to the extent of coronary disease in patients with normal left ventricular systolic function, and returned to baseline level after surgical or catheter revascularization.

Pre-operative coronary revascularization: an optimal therapy for high-risk vascular surgery patients?

Cardiac complications are the leading cause of peri-operative morbidity and mortality of patients undergoing vascular surgery. This high incidence of cardiac complications is related to the presence of underlying coronary artery disease. The optimal treatment strategy for these high-risk patients, including the use of pre-operative coronary revascularization for the purpose of improving peri-operative and long-term cardiac outcomes, has been controversial for several decades. Recently, the results of the Coronary Artery Revascularization Prophylaxis (CARP) trial showed that in the short term there is no reduction in the number of post-operative myocardial infarctions, deaths or length of stay in the hospital, or in long-term outcomes in patients who underwent pre-operative coronary revascularization compared with patients who received optimized medical therapy. In this review, we summarize the role of pre-operative revascularization before elective vascular surgery using current evidence from the CARP trial and of those from published studies.

Prognostic stratification of obese patients by stress 99mTc-tetrofosmin myocardial perfusion imaging

Obesity is a major heath problem associated with increased cardiovascular mortality. There are currently no data to support a role for stress imaging techniques in the risk stratification of obese patients. The aim of this study was to assess the independent value of stress 99mTc-tetrofosmin SPECT in predicting mortality and hard cardiac events in obese patients.

METHODS

We studied 265 patients with a body mass index greater than 30 kg/m2 by exercise or dobutamine stress 99mTc-tetrofosmin myocardial perfusion tomography. Endpoints during follow-up were cardiac death and death of any cause.

RESULTS

The mean patient age (+/-SD) was 59 +/- 10 y, and 110 of the patients were men (42%). The mean body mass index was 37 +/- 7 kg/m2. Scan findings were normal in 113 patients (43%). Myocardial perfusion abnormalities were fixed in 62 patients (23%) and reversible in 90 patients (34%). During a mean follow-up period of 5.5 +/- 2 y, 41 patients (15%) died. Death was considered cardiac in 22 patients (8%). Nonfatal myocardial infarction occurred in 20 patients (7.5%). The annual cardiac death rate was 0.6% in patients with normal perfusion and 3.3% in patients with abnormal perfusion. Patients with a multiple-vessel distribution of abnormalities had a higher cardiac death rate than did patients with a single-vessel distribution (4.1% vs. 2.5%, P < 0.05). The annual mortality rate was 1.3% in patients with normal perfusion and 4.2% in patients with abnormal perfusion. In a multivariate analysis, perfusion abnormalities were independently predictive of cardiac mortality (risk ratio, 3.2; 95% confidence interval, 1.5-6.7) and overall mortality (risk ratio, 2.7; 95% confidence interval, 1.4-4.3).

CONCLUSION

Stress 99mTc-tetrofosmin myocardial perfusion imaging is a useful tool for predicting cardiac and overall mortality in obese patients.

Accuracy of non-invasive techniques for diagnosis of coronary artery disease and prediction of cardiac events in patients with left bundle branch block: a meta-analysis

PURPOSE

Non-invasive evaluation of coronary artery disease (CAD) in patients with left bundle branch block (LBBB) has limitations inherent to different tests, and the relative merits of these tests are unclear. This meta-analysis assessed the accuracy of the frequently used non-invasive techniques, including exercise electrocardiography (ECG), myocardial perfusion imaging (MPI) and stress echocardiography (SE), for detection of CAD and prediction of cardiac events in patients with LBBB.

METHODS

A review was conducted of all reports on detection of CAD and prediction of cardiac events in patients with LBBB (published between January 1970 and December 2004), and revealed 55 diagnostic and nine prognostic reports with sufficient details to calculate test accuracy. Weighted (by sample size) sensitivity and specificity were calculated. Summary relative risk ratios (95% confidence intervals) were calculated.

RESULTS

Overall sensitivity was higher for exercise ECG and (quantitatively analysed) MPI than for SE (83.4% and 88.5% versus 74.6% respectively, p<0.0001). SE had a higher specificity (88.7%) than MPI (41.2%) and exercise ECG (60.1%) (p<0.0001). Based on analysis of eight reports, the relative risk of cardiac death or myocardial infarction in patients with an abnormal SE and MPI was elevated more than sevenfold, but it did not differ by imaging modality (p=0.9).

CONCLUSION

Meta-analysis of non-invasive CAD assessment in LBBB patients revealed that exercise ECG and MPI had the highest sensitivity, while SE had the highest specificity. The prognostic accuracy of MPI and SE appeared similar.

High-Dose -Blockers and Tight Heart Rate Control Reduce Myocardial Ischemia and Troponin T Release in Vascular Surgery Patients

BACKGROUND

Adverse perioperative cardiac events occur frequently despite the use of beta (beta)-blockers. We examined whether higher doses of beta-blockers and tight heart rate control were associated with reduced perioperative myocardial ischemia and troponin T release and improved long-term outcome.

METHODS AND RESULTS

In an observational cohort study, 272 vascular surgery patients were preoperatively screened for cardiac risk factors and beta-blocker dose. Beta-blocker dose was converted to a percentage of maximum recommended therapeutic dose. Heart rate and ischemic episodes were recorded by continuous 12-lead electrocardiography, starting 1 day before to 2 days after surgery. Serial troponin T levels were measured after surgery. All-cause mortality was noted during follow-up. Myocardial ischemia was detected in 85 of 272 (31%) patients and troponin T release in 44 of 272 (16.2%). Long-term mortality occurred in 66 of 272 (24.2%) patients. In multivariate analysis, higher beta-blocker doses (per 10% increase) were significantly associated with a lower incidence of myocardial ischemia (hazard ratio [HR], 0.62; 95% confidence interval [CI], 0.51 to 0.75), troponin T release (HR, 0.63; 95% CI, 0.49 to 0.80), and long-term mortality (HR, 0.86; 95% CI, 0.76 to 0.97). Higher heart rates during electrocardiographic monitoring (per 10-bpm increase) were significantly associated with an increased incidence of myocardial ischemia (HR, 2.49; 95% CI, 1.79 to 3.48), troponin T release (HR, 1.53; 95% CI, 1.16 to 2.03), and long-term mortality (HR, 1.42; 95% CI, 1.14 to 1.76).

CONCLUSIONS

This study showed that higher doses of beta-blockers and tight heart rate control are associated with reduced perioperative myocardial ischemia and troponin T release and improved long-term outcome in vascular surgery patients.

Perioperative cardiac risk stratification and modification in abdominal aortic aneurysm repair

Cardiovascular complications are important causes of morbidity and mortality following vascular surgery. Adequate preoperative risk assessment and perioperative management may modify postoperative mortality and morbidity and improve long-term prognosis. The objective of this review is to examine the present day knowledge regarding the preoperative evaluation and perioperative management of patients undergoing noncardiac surgery, focusing specifically on abdominal aortic aneurysm (AAA) repair. Clinical markers combined with ECG and surgical risk assessment can effectively divide patients in a truly low-risk, intermediate and high-risk population. Low-risk patients can probably be operated on without additional cardiac testing. Notably, due to the surgical risk, AAA patients are never low-risk patients. Intermediate-risk and high-risk patients are referred for cardiac testing to exclude extensive stress induced myocardial ischemia, as beta-blockers provide insufficient myocardial protection in this case and preoperative coronary revascularization might be considered. Whether patients at intermediate risk without ischemic heart disease should be treated with statins and/or beta-blockers is still controversial. In high-risk patients, it is strongly advised to administer beta-blockers with heart rate determined dose adjustment, while the effects of preoperative revascularization remain subject to debate.

Association of plasma N-terminal pro-B-type natriuretic peptide with postoperative cardiac events in patients undergoing surgery for abdominal aortic aneurysm or leg bypass

Postoperative cardiac events are related to myocardial ischemia and reduced left ventricular function. The utility of N-terminal-pro-B-type natriuretic peptide (NT-pro-BNP) for preoperative cardiac risk evaluation has not been evaluated. The objective of this study was to assess whether plasma NT-pro-BNP predicts postoperative cardiac events in patients who undergo major vascular surgery in addition to clinical and dobutamine stress echocardiographic data. One hundred seventy consecutive patients scheduled for major noncardiac vascular surgery were prospectively evaluated by dobutamine stress echocardiographic and NT-pro-BNP measurements. Multivariable logistic regression analysis was performed to evaluate the predictors of cardiac death and nonfatal myocardial infarction during a follow-up of 30-days. Receiver-operating characteristic analysis was performed to determine the optimal cut-off value of NT-pro-BNP to predict outcome. Patients' mean age was 59 +/- 13 years, and 71% were men. The median NT-pro-BNP level was 110 pg/ml (interquartile range 42 to 389). Cardiac events occurred in 2 of 144 patients (1.4%) with NT-pro-BNP <533 pg/ml (i.e., the optimal cut-off value to predict cardiac events) and in 11 of 26 patients (42%) with NT-pro-BNP >or=533 pg/ml (unadjusted odds ratio 52, 95% confidence interval 11 to 256, p <0.0001). After adjustment for cardiac risk factors and dobutamine stress echocardiographic results, NT-pro-BNP remained significantly associated with cardiac events (adjusted odds ratio 17, 95% confidence interval 3 to 106, p = 0.002). In conclusion, in patients scheduled for major vascular surgery, elevated plasma NT-pro-BNP levels are independently associated with an increased risk for postoperative cardiac events. Further studies in a larger number of patients are required to confirm these findings.

Prognostic value of stress 99mTc-tetrofosmin myocardial perfusion imaging in predicting all-cause mortality: a 6-year follow-up study

PURPOSE

The aim of this study was to ascertain whether stress myocardial perfusion imaging can independently predict long-term mortality.

METHODS

We studied 1,386 patients with known or suspected coronary artery disease by means of stress 99mTc-tetrofosmin myocardial perfusion tomography. The end point during follow-up was death from any cause. Mortality rates were compared with that in a reference population using calculated age- and gender-specific data in the general population.

RESULTS

Mean age was 60+/-11 years. There were 608 (44%) women. Perfusion abnormalities were fixed in 416 (30%) patients and reversible in 445 (32%) patients. During a mean follow-up of 6+/-1.9 years, 290 (21%) patients died. The annual mortality was 1.7% in patients with normal perfusion and 5.2% in patients with abnormal perfusion. Patients with multivessel distribution of perfusion abnormalities had the highest annual mortality (6.2%). The annual mortality in the reference population was 3.2%. In a multivariate analysis model, predictors of death were age [risk ratio (RR)=1.06, 95% CI 1.04-1.07], male gender (RR=2, CI 1.6-2.6), history of heart failure (RR=2.3, CI 1.8-3.1), diabetes mellitus (RR=2.1, CI 1.6-2.7), smoking (RR=1.8, CI 1.4-2.3), reversible perfusion defects (RR=1.8, CI 1.4-2.5) and fixed perfusion defects (RR=1.7, CI 1.3-2.1).

CONCLUSION

Myocardial perfusion abnormalities on stress 99mTc-tetrofosmin tomography are independently associated with long-term risk of death. The extent of perfusion abnormalities is a major determinant of mortality. The presence of normal perfusion is associated with a lower mortality compared with the general population.

The impact of hypertension on systolic and diastolic left ventricular function. A tissue Doppler echocardiographic study

BACKGROUND

The purpose of this study is to assess the impact of hypertension on systolic function and diastolic function using 2-dimensional echocardiography, conventional Doppler imaging of the transmitral inflow, and tissue Doppler imaging (TDI) of the mitral annulus.

METHODS

From an outpatient clinic population, 414 consecutive patients underwent 2-dimensional echocardiography, conventional Doppler imaging of the transmitral inflow, and TDI of the septal, lateral, inferior, and posterior walls near the mitral annulus. Parameters of systolic left ventricular (LV) function and diastolic LV function were assessed. Patients were divided according to the presence or absence of systemic hypertension (blood pressure > or = 140/90 mm Hg on > or = 3 measurements or treatment with antihypertensive medication).

RESULTS

A complete echocardiographic evaluation was obtained in 397 patients. Among these, 269 (68%) had hypertension. There was no difference with respect to age between patients with and without hypertension. Patients with hypertension had higher LV mass index and relative wall thickness and lower TDI peak systolic velocity (V(S)) when compared with patients without hypertension. In addition, indices of diastolic LV function were significantly impaired in hypertensive patients.

CONCLUSIONS

Quantitative echocardiography using TDI reveals that hypertensive patients with preserved global LV systolic function often have combined impairment of systolic function and diastolic function.

Mitral regurgitation and left ventricular dyssynchrony: implications for treatment

Cardiac resynchronisation therapy may provide an alternative treatment for mitral regurgitation in patients unsuitable for surgery.

Influence of cardiac risk factors and medication on length of hospitalization in patients undergoing major vascular surgery

Major vascular surgery is associated with a long in-hospital length of stay (LOS). Cardiac risk factors identify patients with an increased risk. Recent studies have associated statin, aspirin, and beta-blocker therapies with improved postoperative outcome. However, the effect of all these factors on LOS has not been defined. Our aims were to determine the effect of cardiac risk factors and (preventive) statin, aspirin, and beta-blocker therapy on LOS and to deduce from these factors a model that predicts LOS. In total, 2,374 patients from 1990 to 2004 were enrolled. Mean LOS was 18 +/- 9 days. Cardiac risk factors that were significantly associated with LOS in the multivariable analysis were age, previous heart failure, hypertension, diabetes mellitus, renal failure, and chronic obstructive pulmonary disease. Statin and aspirin use was associated with a shorter LOS. Beta blockers shortened LOS only in patients with underlying coronary artery disease. Together, these factors explained 14.1% of the variance in LOS. In conclusion, in-hospital LOS in patients who undergo major vascular surgery can be predicted more accurately by clinical cardiac risk factors. A significant decrease in in-hospital LOS was achieved with statin, aspirin, and beta-blocker therapies.

Benefits of coronary revascularisation in diabetic and non-diabetic patients with ischaemic cardiomyopathy: Role of myocardial viability

BACKGROUND

Diabetes mellitus in patients with coronary artery disease is associated with poor outcome. In this study, the relation between myocardial viability, diabetes, coronary revascularisation and outcome was evaluated.

METHODS

129 patients (31 diabetic, 98 non-diabetic) with ischaemic cardiomyopathy underwent dobutamine stress echocardiography to assess myocardial viability. Patients with >or=4 viable segments were defined as viable and patients with <4 viable segments as nonviable. Left ventricular ejection fraction (LVEF) was assessed before and 9-12 months post-revascularisation. At the same time-points, LV volumes were measured to evaluate LV remodelling. Finally, cardiac events were noted during 5-year follow-up.

RESULTS

The extent of viable myocardium was comparable between diabetic and non-diabetic patients. After revascularisation, LVEF increased >or=5% in 44% of diabetic and in 40% of non-diabetic patients. LVEF only improved in patients with viable myocardium. Ongoing LV remodelling occurred in 36% and 35% of diabetic and non-diabetic patients respectively, and was related to non-viability, whereas viability protected against ongoing LV remodelling, both in diabetic and non-diabetic patients. Viability was the only predictor of survival after revascularisation.

CONCLUSIONS

Diabetic, viable patients with ischaemic LV dysfunction exhibit improvement in LVEF post-revascularisation with prevention of ongoing LV remodelling, similar to non-diabetic patients. Myocardial viability was also the only predictor of long-term outcome.

Effects of statins on renal function after aortic cross clamping during major vascular surgery

Ischemic reperfusion injury is an important cause of renal dysfunction after major vascular surgery and increases postoperative morbidity and mortality. The aim of the present study was to assess the effect of statins on renal function in patients at high risk for renal dysfunction, that is, those who underwent suprarenal aortic cross clamping-declamping. Seventy-seven patients (28 statin users, 57 men; mean age 69 +/- 8 years) with normal preoperative renal function requiring suprarenal aortic cross clamping-declamping during vascular surgery from 1995 to 2005 were studied. Creatinine levels were obtained before surgery and on days 1, 2, 3, 7, and 30 after surgery. An analysis-of-variance model for repeated measurements was applied to compare creatinine levels between statin users and nonusers, with adjustment for clamping time and blood loss. There were no differences in baseline clinical characteristics, preoperative creatinine levels (0.93 vs 0.96 mg/dl, p = 0.59), and glomerular filtration rate (79 vs 73 ml/min, p = 0.1). Postoperative creatinine levels during the 30 days after surgery were significantly lower in statin users than in nonusers (analysis-of-variance p <0.01, 1.17 vs 1.98 mg/dl). Postoperative hemodialysis was required (temporarily) in 7 patients (9.1%), all statin nonusers. These findings suggest an association between statin use and preserved renal function after suprarenal aortic clamping.

Diagnostic and prognostic value of non-invasive imaging in known or suspected coronary artery disease

The role of non-invasive imaging techniques in the evaluation of patients with suspected or known coronary artery disease (CAD) has increased exponentially over the past decade. The traditionally available imaging modalities, including nuclear imaging, stress echocardiography and magnetic resonance imaging (MRI), have relied on detection of CAD by visualisation of its functional consequences (i.e. ischaemia). However, extensive research is being invested in the development of non-invasive anatomical imaging using computed tomography or MRI to allow detection of (significant) atherosclerosis, eventually at a preclinical stage. In addition to establishing the presence of or excluding CAD, identification of patients at high risk for cardiac events is of paramount importance to determine post-test management, and the majority of non-invasive imaging tests can also be used for this purpose. The aim of this review is to provide an overview of the available non-invasive imaging modalities and their merits for the diagnostic and prognostic work-up in patients with suspected or known CAD.