ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery - Executive summary: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1996 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery)

These guidelines represent an update of those published in 1996 and are intended for physicians who are involved in the preoperative, operative, and postoperative care of patients undergoing noncardiac surgery. They provide a framework for considering cardiac risk of noncardiac surgery in a variety of patient and surgical situations. The overriding theme of these guidelines is that preoperative intervention is rarely necessary simply to lower the risk of surgery unless such intervention is indicated irrespective of the preoperative context. The purpose of preoperative evaluation is not simply to give medical clearance but rather to perform an evaluation of the patient’s current medical status; make recommendations concerning the evaluation, management, and risk of cardiac problems over the entire perioperative period; and provide a clinical risk profile that the patient, primary physician, anesthesiologist, and surgeon can use in making treatment decisions that may influence short- and long-term cardiac outcomes. The goal of the consultation is to identify the most appropriate testing and treatment strategies to optimize care of the patient, provide assessment of both short- and long-term cardiac risk, and avoid unnecessary testing in this era of cost containment

ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery - Executive summary: A report of the American College of Cardiology/American Heart Association Task Force on practice guidelines (Committee to Update the 1996 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery)

These guidelines represent an update of those published in 1996 and are intended for physicians who are involved in the preoperative, operative, and postoperative care of patients undergoing noncardiac surgery. They provide a framework for considering cardiac risk of noncardiac surgery in a variety of patient and surgical situations. The overriding theme of these guidelines is that preoperative intervention is rarely necessary simply to lower the risk of surgery unless such intervention is indicated irrespective of the preoperative context. The purpose of preoperative evaluation is not simply to give medical clearance but rather to perform an evaluation of the patient’s current medical status; make recommendations concerning the evaluation, management, and risk of cardiac problems over the entire perioperative period; and provide a clinical risk profile that the patient, primary physician, anesthesiologist, and surgeon can use in making treatment decisions that may influence short- and long-term cardiac outcomes. The goal of the consultation is to identify the most appropriate testing and treatment strategies to optimize care of the patient, provide assessment of both short- and long-term cardiac risk, and avoid unnecessary testing in this era of cost containment

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Dipyridamole-thallium imaging: the lazy man\u27s stress test

Dipyridamole-thallium imaging is a relatively safe and accurate method to evaluate myocardial perfusion and stress. It is independent of patient motivation, exercise capacity and antianginal medications. Overall it detects coronary artery disease as well as exercise thallium and has already shown utility in prognostic determinations. The continued use of this test on a wide scale appears warranted and additional large scale experience needs to be critically evaluated

Dipyridamole myocardial perfusion imaging

Dipyridamole is a pharmacologic stressor used in place of exercise for myocardial perfusion imaging in patients who cannot exercise due to various physical limitations. Perfusion studies with dipyridamole can identify coronary artery disease (CAD) as accurately as maximal exercise stress testing. In addition, dipyridamole myocardial perfusion studies are useful to stratify patients according to risk of subsequent cardiac events. As dipyridamole is infused, it blocks the reabsorption and metabolism of adenosine normally produced in the body, producing the desired effect on the heart, coronary hyperemia. Dipyridamole can be used with 201Tl and 99mTc myocardial perfusion tracers, for either planar or SPECT imaging, in patients who cannot exercise or who can only exercise at submaximal levels

The value of perioperative clinical indexes and dipyridamole thallium scintigraphy for the prediction of myocardial infarction and cardiac death in patients undergoing vascular surgery

Background Dipyridamole thallium scintigraphy has previously been shown to have predictive value for both perioperative and late cardiac events in patients undergoing vascular surgery. However, despite the prognostic utility of this technique, the relative importance of clinical factors and scintigraphic information is not well known. The purpose of this study was to evaluate the value of commonly used clinical risk indexes, composed of historic variables, and dipyridamole thallium scintigraphy for predicting perioperative cardiac event-free survival rates. Methods and Results Clinical and scintigraphic variables in 360 patients undergoing vascular surgery were analyzed for their predictive utility for perioperative and late (up to 5 years) cardiac events (nonfatal myocardial infarction or cardiac death) by means of chart review and telephone contact. Patients were correctly categorized as being at low, moderate, or high risk for perioperative cardiac events based on two clinical indexes. Thallium redistribution, however, was a more powerful predictor of cardiac events than these indexes. Even in a clinically low-risk patient cohort, the odds ratio for an event increased by 6- to 8-fold ( p<0.05) if thallium redistribution was noted. These indexes also demonstrated prognostic utility for late cardiac event-free survival rates by life-table analysis ( p<0.001). The presence of a fixed thallium defect was associated with an increased risk of late cardiac events ( p<0.01). When stratified by risk index, in those patients at moderate to high risk who had a fixed defect the odds ratio increased by 3.9- to 5.4-fold ( p<0.001). Likewise, the low-risk subgroup had a 3.9- to 8.2-fold increase in the risk of a late cardiac event when a fixed perfusion defect was present. Conclusions Preoperative clinical indexes are predictive of both perioperative and late cardiac events in patients undergoing vascular surgery. However, dipyridamole thallium scintigraphy is more powerful prognostically than these clinical indexes and provides supplemental value to clinical risk stratification

Comparison of hypoxia and ouabain effects on the myocardial uptake kinetics of technetium-99m hexakis 2-methoxyisobutyl isonitrile and thallium-201

Effects of hypoxia and ouabain on transcapillary exchange of [99mTc]hexakis (2-methoxyisobutylisonitrile) [SESTAMIBI, also known as MIBI or HEXAMIBI] and 201TI were investigated with indicator-dilution studies using isolated rabbit hearts. Peak myocardial extraction (Emax), permeability-surface area products (PScap), and net myocardial extraction (Enet) were compared among serial injections during constant coronary flows. Overall, measures of transcapillary transport (Emax and PScap) for SESTAMIBI were significantly lower (p less than 0.001) than those simultaneously determined for thallium, but estimates of tissue retention (Enet) for SESTAMIBI and thallium were not statistically distinguishable. Hypoxia had no significant effect on mean (+/- s.d.) Emax for SESTAMIBI (0.31 +/- 0.13) or thallium (0.59 +/- 0.11), nor on mean PScap or Enet values. Ouabain (1.5 X 10(-7) M and 1.5 X 10(-6) M) had no effect on SESTAMIBI or thallium Emax (respectively, 0.29 +/- 0.08 and 0.60 +/- 0.05) or on PScap for SESTAMIBI. Thallium PScap was depressed with higher ouabain dose (control, 1.22 +/- 0.40; high ouabain, 1.06 +/- 0.41 ml/min/g; p less than 0.01). Ouabain also caused a significant and progressive increase in average SESTAMIBI Enet (control, 0.23 +/- 0.10 to high ouabain, 0.33 +/- 0.12; p less than 0.05), but depressed thallium Enet (control, 0.38 +/- 0.14 to high ouabain, 0.32 +/- 0.18; p less than 0.01). These results suggest myocardial metabolic and/or functional status have minor influence on transcapillary transport of SESTAMIBI and thallium, but significantly affects cellular retention

Comparative myocardial extraction of two technetium-labeled BATO derivatives (SQ30217, SQ32014) and thallium

The transcapillary exchange of a new class of 99mTc-labeled compounds (BATO) were compared to 201Tl in isolated, blood perfused rabbit hearts. During variable blood flow (0.15-2.44 ml/min/g), peak and net extraction (Emax and Enet, respectively), and capillary permeability-surface area product (PScap) were determined with paired indicator-dilution techniques. Serial bolus injections of 201Tl, [111In]albumin, and [99mTc]BATO; chloro[tris(cyclohexanedionedioxime)methyl boronic acid]Tc (SQ30217, n = 8) and a hydroxy-substituted derivative (SQ32014, n = 5) were given to a total of 13 hearts. Mean (+/- s.d.) SQ30217 Emax and Enet were 0.72 +/- 0.09 and 0.55 +/- 0.18, respectively, which were higher than thallium values of 0.57 +/- 0.10 and 0.46 +/- 0.17 (p less than 0.03). Mean SQ30217 PScap was 1.1 +/- 0.4 ml/min/g and was also higher than corresponding thallium determinations (0.7 +/- 0.3; p less than 0.001). SQ32014 Emax, Enet, and PScap were all significantly less than thallium values (p less than 0.001). Thallium and SQ30217 values for Emax and PScap were closely correlated with blood flow (r greater than or equal to 0.73), whereas those for SQ32014 were weakly correlated (r = 0.09). A small clinical pilot study (n = 3) was performed, which showed that SQ32014 was a poor myocardial perfusion agent in man. In summary, transcapillary exchange of SQ30217 is greater than thallium, which in turn, is greater than SQ32014. Therefore, SQ30217 appears to have good clinical potential, but SQ32014 does not

Dipyridamole-thallium scintigraphy predicts perioperative and long-term survival after major vascular surgery

The purpose of this study was to evaluate the ability of dipyridamole-thallium scintigraphy to predict perioperative and late cardiac events after peripheral vascular operations. A total of 262 patients had dipyridamole-thallium scintigraphy before 87 infrainguinal reconstructions, 108 abdominal aortic aneurysm operations, and 67 aortobifemoral bypass grafts that were placed for occlusive disease. Follow-up extended to 5 years (mean, 31.1 months). Logistic regression analysis selected dipyridamole-thallium scintigraphy redistribution as the best predictor of perioperative events. Fixed defects were not predictive. A Cox proportional hazards model for a variety of clinical risk factors and scan parameters identified fixed defects and a history of congestive heart failure as the strongest predictors of late cardiac events. The presence of greater than 1 or 2 fixed segments were the best predictors in patients with an abnormal scan; redistribution did not predict late events. The risk of combined perioperative or late cardiac events was 29% for infrainguinal, 19% for abdominal aortic aneurysm, and 7.5% for aortobifemoral operations. Life-table analysis showed that after a cluster of perioperative events that occurred primarily in patients with dipyridamole-thallium scintigraphy redistribution, most of the late cardiac morbidity and deaths occurred in patients with fixed defects

Prognostic value of dipyridamole thallium scintigraphy for evaluation of ischemic heart disease

Exercise testing alone or in combination with thallium scintigraphy has significant prognostic value. In contrast, dipyridamole thallium imaging is not dependent on patients achieving adequate levels of exercise, but no long-term prognostic studies have been reported. Accordingly, imaging results of 516 consecutive patients referred for dipyridamole thallium studies were correlated with subsequent cardiac events, death (n = 23) and myocardial infarction (n = 43) over a mean follow-up period of 21 months. Patients with a history of congestive heart failure, prior myocardial infarction, diabetes mellitus or abnormal scans were significantly more likely to have a cardiac event (p < 0.03). With use of logistic regression analysis, an abnormal scan was an independent and significant predictor of subsequent myocardial infarction or cardiac death and increased the relative risk of any event more than threefold. The presence of redistribution on thallium scanning further increased the risk of a cardiac event. Survival analysis demonstrated a significant difference between patients with an abnormal or normal thallium scan over a 30 month period. In conclusion, dipyridamole thallium scintigraphy demonstrates prognostic value in a large unselected population and may be an adequate clinical alternative to physiologic exercise testing in the evaluation of coronary heart disease