Dipyridamole Thallium Research Articles

Association of Long Noncoding RNA Expression Signatures with Stress-Induced Myocardial Perfusion Defects.

Stress-induced myocardial perfusion defects found in dipyridamole-thallium-201 single-photon emission computed tomography imaging may indicate vascular perfusion abnormalities and risk of obstructive or nonobstructive coronary heart disease. Besides nuclear imaging and subsequent coronary angiography (CAG), no blood test can indicate whether dysregulated homeostasis is associated with stress-induced myocardial perfusion defects. This study investigated the expression signature of long noncoding RNAs (lncRNAs) and genes involved in vascular inflammation and stress response in the blood of patients with stress-induced myocardial perfusion abnormalities (n = 27). The results revealed an expression signature consisting of the upregulation of RMRP (p < 0.01) and downregulations of THRIL (p < 0.01) and HIF1A (p < 0.01) among patients with a positive thallium stress test and no significant coronary artery stenosis within 6 months after baseline treatment. We developed a scoring system based on the expression signatures of RMRP, MIAT, NTT, MALAT1, HSPA1A, and NLRP3 to predict the need for further CAG among patients with moderate-to-significant stress-induced myocardial perfusion defects (area under the receiver operating characteristic curve = 0.963). Therefore, we identified a dysregulated expression profile of lncRNA-based genes in the blood that could be valuable for the early detection of vascular homeostasis imbalance and personalized therapy.

The clinical usefulness of phase analysis in detecting coronary artery disease using dipyridamole thallium-201-gated myocardial perfusion imaging with a cadmium-zinc-telluride camera

BackgroundPrevious studies have demonstrated left ventricular mechanical dyssynchrony (LVMD) in patients with severe coronary artery disease (CAD) with ≥ 70% stenosis. The aim of this study was to evaluate the clinical usefulness of stress/rest LVMD in the diagnosis of CAD with ≥ 50% stenosis using dipyridamole thallium-201 (Tl-201) myocardial perfusion imaging (MPI) with a cadmium-zinc-telluride camera. Methods and ResultsA total of 476 patients without known CAD who underwent dipyridamole Tl-201 MPI and coronary angiography within 6 months were retrospectively reviewed. LVMD parameters including phase standard deviation and phase histogram bandwidth, phase skewness and phase kurtosis, as well as myocardial perfusion and myocardial stunning were assessed in post-stress and rest MPI. Relationships between the presence of CAD on coronary angiography and single photon emission computerized tomography (SPECT) parameters were evaluated. The presence of perfusion abnormalities was the best diagnostic tool in detecting CAD. Although less left ventricular synchrony was observed post-stress in the CAD group compared to the non-CAD group, no significant dyssynchrony was noted. ConclusionsThe addition of phase analysis to help diagnose CAD in Tl-201-gated SPECT with dipyridamole stress may have limited value in patients with CAD with ≥ 50% stenosis.

The Effect of Long Term Smoking as an Independent Coronary Risk Factor on Myocardial Perfusion Detected by Thallium 201 or Tc99m Sestamibi Spect Study

Objective: The aim of this work was to assess the effect of smoking as an independent coronary risk factor on Myocardial Perfusion detected by Thallium 201 or Tc99m Sesta MIBI SPECT study.Methods: This study included 200 patients, 100 who are smokers only (group A) without any cardiac risks and the other 100 (group B) were nonsmokers, but with single cardiac risk factor as hypertension or diabetes. Each was subjected to Dipyridamole (smokers 53, 47) or exercise (nonsmokers 51, 49) Thallium-201 or Tc99m SestaMIBI SPECT protocol.Results: Comparing smokers versus nonsmokers who have another one risk factor, smokers had : Lower age with ischemic heart disease 55 years versus 60 years; Higher heart rate during peak stress; higher blood pressure during peak stress; More incidence of chest pain during stress test; had the same degree of ischemic perfusion defect, but higher incidence of persistent LV dilatation (43% versus 28%), higher incidence of severe perfusion defects (68% versus 53%) and statistically significant higher incidence of scar tissue (52% versus 30%).Conclusion: Smoking is an independent risk factor equal to hypertension and diabetes but smokers has higher incidence of severe perfusion defects and scar.

Applying preoperative dipyridamole thallium-201 scintigraphy for preventing cardiac mortality and complications for patients with secondary hyperparathyroidism undergoing parathyroidectomy

To evaluate the value of preoperative dipyridamole thallium-201 scintigraphy for reducing cardiovascular complication in secondary hyperparathyroidism (SHPTH) patients. Thallium scintigraphy was arranged for all dialysis patients who underwent parathyroidectomy from Jan 2011 to July 2015. Management of defects on thallium scintigraphy included cardiac catheterization and ultrasonography. Analysis includes 30-day mortality, morbidity and the predicting factors for thallium scintigraphy defect. Of 249 patients with SHPTH, 19 (7.6%) had defects on thallium scintigraphy, 15 (88%) of whom had coronary artery disease on angiography. History of acute coronary syndrome (ACS, p<0.001), diabetes mellitus (DM, p=0.03), male sex (p=0.03), and higher body mass index (BMI, p=0.001) were significant predictors of positive thallium scintigraphy results. History of ACS was the most significant predictor after adjustment in the multivariate logistic analysis (odds ratio, 22.56; 95% confidence interval, 7.02-72.53). All the patients survived the 30-day postoperative period, with minimal cardiovascular morbidity. Preoperative dipyridamole thallium-201 scintigraphy is useful for SHPTH patients to minimized surgical mortality and morbidity.

A study on the role of ECG, echo and dipyridamole thallium scan in identifying early myocardial damage in systemic sclerosis

A study on the role of ECG, echo and dipyridamole thallium scan in identifying early myocardial damage in systemic sclerosis

Preoperative Cardiac Evaluation by Dipyridamole Thallium‐201 Myocardial Perfusion Scan Provides no Benefit in Patients with Abdominal Aortic Aneurysm

The purpose of the present study was to evaluate the benefits of a preoperative dipyridamole thallium-201 myocardial perfusion scan in patients undergoing abdominal aortic aneurysm (AAA) repair. We retrospectively reviewed findings in a prospectively collected database of patients undergoing open or endovascular repair of AAA at the Asan Medical Center, Seoul, Korea, from January 2001 to May 2011. Of 373 patients, 11 (2.9 %) had postoperative myocardial infarction (MI), whereas 24 (6.4 %), 17 (4.6 %), 24 (6.4 %), and 8 (2.1 %) were diagnosed with myocardial ischemia, atrial fibrillation, ventricular arrhythmia, and congestive heart failure, respectively. The incidence of 30-day cardiac-related mortality was 1.6 % (6 of 373 patients). The preoperative variables significantly associated with postoperative cardiac events in multivariate analysis were preoperative congestive heart failure (odds ratio [OR] 8.8, 95 % confidence interval [CI] 1.36-56.73, p = 0.022), long-acting nitrates (OR 8.1, 95 % CI 1.22-54.26, p = 0.03), and body mass index (BMI) higher than 26 (OR 3.6, 95 % CI 1.49-8.48, p = 0.004). The variables obtained from dipyridamole thallium-201 myocardial perfusion scan were not correlates of postoperative cardiac events. The sensitivity of reversible defects for postoperative cardiac events was 14 % and the specificity was 90 %. Subgroup analyses revealed that thallium defects were not significant variables in predicting postoperative cardiac events in patients with coronary artery disease (CAD) or in no-CAD patients. Preoperative dipyridamole thallium-201 myocardial perfusion scans were ineffective in predicting postoperative cardiac complications in AAA patients. These results suggest that the routine use of these tests for preoperative screening of patients undergoing AAA repair may not be warranted.

Hemodynamic response, arrhythmic risk, and overall safety of Regadenoson as a pharmacologic stress agent for myocardial perfusion imaging in chronic obstructive pulmonary disease and bronchial asthma patients

Regadenoson (REG) is a A2a receptor selective pharmacologic SPECT imaging agent. Its safety in unselected chronic obstructive pulmonary disease (COPD) or asthma (AM) undergoing SPECT imaging has not been well evaluated. We retrospectively identified 228 patients (COPD n = 126 and AM n = 102, Grp 1) undergoing REG SPECT from Jan to Nov 2009 and compared to 1,142 patients without COPD and AM (control, Grp 2). A standard 400 μg REG bolus was used and gated Tc-99 m tetrofosmin SPECT done. Patient demographics, REG SPECT data, side effects, arrhythmia occurrences, and any exacerbation of COPD or AM leading to treatment, hospitalization or death were evaluated. The side effect profile of Grp 1 was also compared to a historical cohort who underwent intravenous dipyridamole thallium-201 imaging and adenosine SPECT. Both groups were comparable with regards to baseline characteristics. There was 0% incidence of clinical exacerbation of COPD or AM after REG. COPD patients had more non-significant arrhythmias (58.3% vs. Grp 2, 43%, P = 0.004). There was 0% incidence of any atrio-ventricular block and only 2 instances of brief supraventricular tachycardia. When compared to the historical cohort of COPD who underwent IV dipyridamole thallium imaging, COPD in Grp 1, had more dyspnea and flushing and when compared to COPD/AM patients who underwent adenosine SPECT, Grp 1 pts had more of flushing and headache (24.9% vs. 2.8%, P = <0.001) but less of bronchospasm (1.3% vs. 6.9%, P = 0.022) and AV block (0% vs. 4.2%, P = 0.014). REG SPECT can be safely performed in COPD and AM population.

Direct comparison between pharmacological stress with adenosine triphosphate disodium and exercise stress myocardial perfusion imagings

To clarify the significance of adenosine triphosphate disodium stress myocardial perfusion imaging (ATP-MPI), we directly compared the findings of ATP-MPI with those of exercise stress myocardial perfusion imaging (Ex-MPI). ATP-MPI, Ex-MPI, and coronary angiography (CAG) were performed within 60 days in 17 coronary artery disease patients with mean age of 62.1+/-7.9 years. CAG revealed single-vessel disease (SVD) in 10 patients and multivessel disease (MVD) in seven patients. The summed stress score (SSS) of ATP-MPI was significantly higher than that of Ex-MPI (10.0 [7.8-14.3] vs. 8.0 [4-18], P<0.05). No difference in the SSS was observed between ATP-MPI and Ex-MPI in patients with SVD (8.0 [6.0-9.0] vs. 8.0 [6.0-10.0], NS), whereas this difference was significant in patients with MVD (15.0 [14.0-22.8] vs.9 [7.3-16.3], P<0.05). There was no difference in the summed rest score between ATP-MPI and Ex-MPI. The univariate logistic analysis showed that "MVD" was the significant factor influencing to the overt discrepancy between ATP-MPI and Ex-MPI (odds ratio: 9.0, 95% confidence interval: 1.07-75.84, P=0.043). The accuracy of ATP-MPI and Ex-MPI in detecting the territory of stenotic coronary vessel or previous myocardial infarction was 98.0% and 92.1% (NS), respectively. In conclusion, ATP-MPI is useful for detecting potential ischemic areas that cannot be detected by Ex-MPI, particularly in patients with MVD.

Resting Chest Pain, Negative Treadmill Exercise Electrocardiogram, and Reverse Redistribution in Dipyridamole Myocardial Perfusion Scintigraphy Might be the Features of Coronary Artery Spasm

Coronary artery spasm usually attacks while at rest and the diagnosis depends on provoking tests which mostly are invasive, expensive and not practical. Previous investigations demonstrated that in most patients with coronary artery spasm, treadmill exercise electrocardiography (TEEC) did not induce any ischemic changes, and myocardial perfusion scintigraphy (MPS) showed reverse redistribution (RR). Combination of resting chest pain, negative TEEC and RR might be a rational noninvasive set to predict coronary artery spasm. Patients with chest pain at rest, no significant coronary artery stenosis, and willing to undergo acetylcholine test were included. TEEC, dipyridamole and rest thallium-201 MPS were performed before or after coronary angiography. The patients were divided into spasm and nonspasm groups by acetylcholine test. The clinical features and results of TEEC and MPS were compared between the spasm and nonspasm groups. Acetylcholine test was performed in 92 patients and coronary artery spasm was successfully provoked in 68 patients. Positive TEEC was induced in only 4 patients in the spasm group. RR was present in totally 77 patients and 68 of them were from the spasm group. By a combination of resting chest pain, negative TEEC and RR to diagnose coronary artery spasm, the sensitivity and specificity were 94% and 96% respectively. Combination of resting chest pain, negative TEE and RR appears to be a rational noninvasive set to predict coronary artery spasm.

Intravascular Ultrasound Correlates with Coronary Flow Reserve and Predicts the Survival in Angiographically Normal Cardiac Transplant Recipients

Objectives: We aimed to determine whether epicardial and intramyocardial arteries were involved concordantly in early cardiac allograft vasculopathy. Methods: Thirty consecutive recipients who had received cardiac transplantation more than 1 year before and had a normal coronary angiogram were enrolled for intravascular ultrasound (IVUS), fractional flow reserve, coronary flow reserve and dipyridamole thallium-201 single photon emission computed tomography. Graft failure including cardiac death and retransplantation served as the primary outcome. Results: Plaque volume index and maximum area stenosis calculated from IVUS measurements correlated with coronary flow reserve deterioration in a subgroup of patients with normal fractional flow reserve (n = 13; r = –0.80, p = 0.001 and r = –0.91, p <0.0001, respectively). After follow-up for 18.4 ± 7.6 months, maximum area stenosis was found to be an independent predictor of graft failure (hazard ratio 1.43, 95% confidence interval 1.08–1.89, p = 0.012). Conclusion: In patients with physiologically normal epicardial coronary arteries, impairment of microvascular integrity correlates with the plaque burden measured by IVUS, suggesting the concordant involvement of both epicardial and resistant vessels in early cardiac allograft vasculopathy. Evident epicardial coronary narrowing on IVUS may predict graft failure in spite of normal coronary angiograms.

MEDICAL THERAPY CAN SIGNIFICANTLY IMPROVE EXERCISE TOLERANCE IN ISOLATED DIASTOLIC HEART FAILURE.

Background Patients with preserved left ventricular ejection fraction and signs and symptoms of heart failure are defined as having diastolic heart failure (DHF). Evidence-based therapies for this disorder are not clearly defined. We present three cases, which derived significant benefit from different medical regimens tailored to the individual patient. Case 1 A 66-year-old, hypertensive male referred for assessment of his progressive shortness of breath (SOB). SOB had worsened over the past 6 months to the point of being unable to walk half a block without symptoms. Echocardiogram revealed a preserved ejection fraction with reversal of the E:A ratio. Lung/heart ratio on dipyridamole thallium scan was elevated at 0.67. His DHF was treated by starting ramipril and increasing his metoprolol. After treatment, he noted that he was able to use his stationary bike for 15 to 20 minutes without dyspnea. Case 2 A 49-year-old hypertensive obese female presented with retrosternal chest discomfort associated with worsening SOB after walking only 10 feet. Cardiac catheterization revealed an elevated end-diastolic pressure of 40 mm Hg but no evidence of coronary artery disease. Echocardiogram showed moderate left ventricular hypertrophy with a preserved ejection fraction. She was initially started on benazepril and metoprolol, with spironolactone added later. Her distance walked had increased to one block since beginning treatment. Case 3 A 54-year-old female presented to the emergency department complaining of exhaustion and SOB after walking only one-tenth of a mile for the past 3 weeks. Cardiac catheterization showed nonobstructive coronaries with an LVEDP of 38mmHg. Echocardiogram showed a preserved ejection fraction with a right ventricular systolic pressure of 53 mm Hg and impaired relaxation. She was initially treated with losartan, spironolactone, Isordil, Lasix, and hydrochlorothiazide. Verapamil was added later in a follow-up visit, with further improvement in symptoms. Later, verapamil was stopped and Toprol XL was added. However, as her symptoms of SOB worsened, verapamil was reinstated. SOB improved by restarting the verapamil. She is now able to walk 450 feet with relative ease, whereas prior to hospitalization, she could only walk 50 feet before becoming tired and SOB. Conclusions We presented three patients with DHF who responded to individually tailored medical regimens, resulting in a 100 to 1,000% increase in exercise tolerance. Medical therapy for DHF can produce striking improvement in quality of life. Precise medical therapy and hierarchy of its implementation remain to be defined.

Cardiovascular Magnetic Resonance Imaging Has Much to Offer in the Assessment of Renal Transplant Recipients

To the Editor: In her review of cardiac assessment for renal transplantation, Pilmore (American Journal of Transplantation 2006; 6: 659–665) comprehensively assesses current methods for screening for coronary artery disease in patients with end-stage renal failure (ESRF) using myocardial perfusion studies with thallium scintography, dobutamine echocardiography and dipyridamole thallium scans (1Pilmore H Cardiac assessment for renal transplantation..Am J Transplant. 2006; 6: 659-665Abstract Full Text Full Text PDF PubMed Scopus (51) Google Scholar). Recent developments in cardiac imaging with cardiac magnetic resonance imaging (CMR) suggest that this technique may also have much to offer in work-up of the renal transplant recipient. This is a promising method for noninvasive evaluation of myocardial perfusion as well as allowing detailed assessment of cardiac structure and function. Studies suggest that CMR is more accurate than radionuclide imaging at detecting small areas of myocardial infarction (2Wagner A Mahrholdt H Holly TA et al.Contrast-enhanced MRI and routine single photon emission computed tomography (SPECT) perfusion imaging for detection of subendocardial myocardial infarcts: An imaging study..Lancet. 2003; 361: 374-379Abstract Full Text Full Text PDF PubMed Scopus (1075) Google Scholar), which are likely to have therapeutic and prognostic implications for patients on the transplant list. Furthermore, while Pilmore rightly points out that data are lacking on the benefits of pre-emptive coronary revascularization of patients with ESRF, CMR can identify viable myocardium, therefore allowing appropriate selection of individual patients for revascularization procedures (3Kim RJ Wu E Rafael A et al.The use of contrast-enhanced magnetic resonance imaging to identify reversible myocardial dysfunction..N Engl J Med. 2000; 343: 1445-1453Crossref PubMed Scopus (2591) Google Scholar). This is particularly important given the high mortality of patients with ESRF undergoing coronary revascularization. Our experience using CMR as research tool in patients being assessed for renal transplantation has confirmed a high incidence of myocardial ischemia (Figure 1) (4Mark PB Johnston N Groenning BA et al.Redefinition of uremic cardiomyopathy by contrast-enhanced cardiac magnetic resonance imaging..Kidney Int. 2006; (Epub 2006 Mar 1.)Abstract Full Text Full Text PDF Scopus (205) Google Scholar). Moreover with CMR we found that left ventricular dysfunction did not occur in the absence of myocardial ischemia, suggesting that left ventricular dysfunction in a patient with ESRF is highly suggestive of underlying coronary artery disease. This should be investigated aggressively with angiography in addition to medical therapy with beta-blockade, anti-platelet therapy and renin-angiotensin system inhibition as appropriate. Prospective study of patients studied with CMR is ongoing to assess the impact of its use and the relationship between CMR findings and long-term outcomes for both transplanted patients and those remaining on the wait list. From a practical point of view CMR is noninvasive, does not use ionizing radiation (unlike radionuclide studies and CT angiography) and therefore is appropriate for performing repeated scans on transplant listed patients. Stress perfusion CMR, using pharmacological agents such as adenosine to induce coronary hyperaemia, has a high sensitivity and specificity for the presence of significant coronary artery stenoses (5Plein S Radjenovic A Ridgway JP et al.Coronary artery disease: Myocardial perfusion MR imaging with sensitivity encoding versus conventional angiography..Radiology. 2005; 235: 423-430Crossref PubMed Scopus (115) Google Scholar). Although nephrotoxicity has been reported with gadolinium-based contrast agents used for CMR, these are generally felt to be safe in renal insufficiency, and certainly safer than radiocontrast agents used for both conventional and CT coronary angiography. This allows CMR to facilitate comprehensive noninvasive cardiac assessment of the patient with advanced kidney disease, hoping to undergo pre-emptive renal transplantation, by detailing cardiac structure, function, assessing myocardial perfusion and viability, should revascularization be contemplated. The argument could be made that CMR is expensive and not widely available. As its use is expanding and it integrates the results of multiple tests in a safe repeatable manner, potentially reducing the need for invasive investigations, these obstacles may be surmounted. The renal transplant community is ideally placed to embrace this technology that may progress from being a research tool to representing a ‘one stop’ screening investigation for potential transplant recipients. P.B. Mark is funded by a British Heart Foundation Junior Fellowship.

Long-term results of elective open repair for abdominal aortic aneurysm

腹的大动脉的动脉瘤(AAA ) 有高倾向破裂。自从他们，由有接枝的常规外科的代替的修理 ofAAA 是治疗的标准标志 1960 年代。因为进展在外科，麻木并且特别护理技术，选任的开的 AAA 修理的结果常常改善了。与 endovasculartechniques 的改进，然而，开的修理的角色正在被质问。越来越多的 stents 正在被部署住院病人因为他们的不太侵略的特征。我们我们经验的十年关于 endoluminal 和开的修理与选任的开的 AAA 修理和最近的报纸考察了让 AAA 在中国为 AAA 讨论开的修理的地位和未来。

Worsening of left ventricular ejection fraction induced by dipyridamole on Tl-201 gated myocardial perfusion imaging predicts significant coronary artery disease

Vasodilator stress on myocardial perfusion imaging has been found to induce ischemic stunning, which may present as transient worsening of left ventricular ejection fraction (LVEF) or regional wall motion abnormality. This study aimed to evaluate the significance of stress-induced worsening of LVEF in the diagnosis of coronary artery disease (CAD) on dipyridamole thallium 201 gated single photon emission computed tomography (SPECT). The study included 126 patients who underwent dipyridamole Tl-201 gated SPECT and coronary angiography within 3 months. Poststress and 4-hour rest images were obtained, and LVEF was calculated by use of automated software (QGS 3.0). A decrease in LVEF of 6% or greater from rest to poststress was considered significant, and this threshold was determined by the serial reproducibility assessment of Tl-201 gated SPECT. If worsening of LVEF was used as the criterion for detecting significant CAD (> or = 70% coronary stenoses in > or = 1 vessel), the sensitivity, specificity, positive predictive value, and negative predictive value were 35%, 93%, 90%, and 44%, respectively. Dipyridamole-induced worsening of LVEF, as shown by Tl-201 gated SPECT, is a valuable nonperfusion marker of significant CAD. Although the sensitivity of LVEF worsening in detecting significant CAD is only 35%, the specificity is as high as 93%.

The Value of Computed Tomography-Derived Coronary Artery Calcification Score in Coronary Artery Disease Detection in Asymptomatic Hemodialysis Patients

Background. We evaluated the value of coronary artery calcification (CAC) score in coronary artery disease (CAD) detection in asymptomatic hemodialysis (HD) patients by evaluating the association among CAC score, exercise electrocardiography (EECG), and Thallium-201 dipyridamole scintigraphy. Correlation between aortic pulse wave velocity (PWV) and CAC score was also evaluated. Methods. CAC score was assessed with conventional computed tomography in 40 patients. Thirty patients completed EECG and 25; those with a positive CAC score and/or a positive EECG performed Thallium dipyridamole scintigraphy. Carotid-femoral PWV was assessed in all patients. Results. There was no association among CAC score and EECG or Thallium dipyridamole scintigraphy. In contrast, CAC score was correlated with aortic PWV. Conclusion. The previous results question the role of CAC score in the detection of CAD in asymptomatic HD patients. The correlation between CAC score and aortic PWV raises the possibility that CAC score represents more an indicator of coronary artery medial wall calcification than a marker of CAD.

Perioperative myocardial injury: individual and population implications

It is generally understood that patients who have cardiovascular disease are at risk of cardiac complications after surgery. In patients undergoing major or vascular surgery, the risk of such complications can be signi®cant. Eagle and colleagues studied patients enrolled on the CASS (Coronary Artery Surgery Study) registry who subsequently underwent non-cardiac surgery. They reported a perioperative myocardial infarction rate of 8.5% in patients with medically managed coronary artery disease who underwent vascular surgery. The authors de®ned high-risk surgery as surgery associated with a risk of perioperative death or myocardial infarction of greater than 4%. Abdominal surgery, thoracic surgery, and head and neck surgery fell into this category. For patients undergoing these types of surgery who had medically treated coronary artery disease, the overall perioperative myocardial infarction rate was 2.7% and the overall death rate 3.3%. This compared with rates of 0.8 and 1% respectively in patients undergoing similar surgery who did not have coronary artery disease. Data such as these are often considered with information on the prevalence of coronary artery disease to obtain some indication of the population burden of disease. For example, in 1990 Mangano stated that 25 million patients undergo major surgery in the USA each year and suggested that perhaps 6±7 million of these people are at risk of perioperative cardiac complications. Such estimates suggest that perioperative cardiac complications are both a major issue in the care of individual surgical patients and a major public health issue. This review will examine in more detail the population impact of perioperative cardiac morbidity and the implications of this for the individual patient.

A trial of a half-dose of dipyridamole thallium-201 myocardial perfusion imaging to detect coronary artery disease

A trial of a half-dose of dipyridamole thallium-201 myocardial perfusion imaging to detect coronary artery disease

Quantitative analysis of left ventricular regional wall motion with color kinesis during abdominal aortic cross-clamping

Objectives The authors aimed to establish a technique for quantitative analysis of regional wall motion abnormality (RWMA) using color kinesis (CK) of transesophageal echocardiography (TEE) in surgical patients. This technique was used to determine whether RWMAs develop de novo after infrarenal aortic cross-clamping in patients undergoing vascular surgery with a preoperative dipyridamole thallium stress test (DTST). Design An observational study. Setting University hospital. Participants Thirty-eight patients undergoing infrarenal abdominal aortic aneurysm resection or aortofemoral bypass. Measurements and main results CK images of the left ventricle (LV) were obtained from the midventricular transgastric short-axis view before and after infrarenal aortic cross-clamping using TEE and analyzed off-line using custom software. The predictive value of the category “reversible perfusion defect” (RD) was also estimated from DTST for predicting new RWMAs with CK. CK analysis is suitable for clinical use based on the comparison with conventional two-dimensional echocardiogram measurements and interobserver variability. CK analysis showed all 7 patients with persistent perfusion defects on DTST had RWMAs. New RWMAs occurred in 2 of 9 patients with RD and in 2 of 15 patients with normal DTST, indicating that there was no significant difference between RD and normal DTST in the incidence of new RWMAs. Conclusions A new method is available for clinical use, which is capable of visualizing RWMAs. These results suggest that new RWMAs introduced by aortic cross-clamping occur irrespective of the risk as assessed by preoperative DTST. CK with the new analysis method might be a useful tool to quantitatively evaluate RWMAs during surgery.

Functional abnormalities in patients with permanent right ventricular pacing: The effect of sites of electrical stimulation

ObjectivesWe sought to evaluate the long-term effects of alternative right ventricular pacing sites on myocardial function and perfusion. BackgroundPrevious studies have demonstrated that asynchronous ventricular activation due to right ventricular apical (RVA) pacing alters regional myocardial perfusion and functions. MethodsWe randomized 24 patients with complete atrioventricular block to undergo permanent ventricular stimulation either at the RVA (n = 12) or right ventricular outflow (RVOT) (n = 12). All patients underwent dipyridamole thallium myocardial scintigraphy and radionuclide ventriculography at 6 and 18 months after pacemaker implantation. ResultsAfter pacing, the mean QRS duration was significantly longer during RVA pacing than during RVOT pacing (151 ± 6 vs. 134 ± 4 ms, p = 0.03). At six months, the incidence of myocardial perfusion defects (50% vs. 25%) and regional wall motion abnormalities (42% vs. 25%) and the left ventricular ejection fraction (LVEF) (55 ± 3% vs. 55 ± 1%) were similar during RVA pacing and RVOT pacing (p > 0.05). However, at 18 months, the incidence of myocardial perfusion defects (83% vs. 33%) and regional wall motion abnormalities (75% vs. 33%) were higher and LVEF (47 ± 3 vs. 56 ± 1%) was lower during RVA pacing than during RVOT pacing (all p < 0.05). Patients with RVA pacing had a significant increase in the incidence of myocardial perfusion defects (p < 0.05) and a decrease in LVEF (p < 0.01) between 6 and 18 months, but patients with RVOT pacing did not (p > 0.05). ConclusionsThis study demonstrates that preserved synchronous ventricular activation with RVOT pacing prevents the long-term deleterious effects of RVA pacing on myocardial perfusion and function in patients implanted with a permanent pacemaker.

Assessment of myocardial perfusion during pharmacologic contrast stress echocardiography

We believe that using MCE simultaneously with a dipyridamole stress protocol and thallium-201 SPECT for the detection of coronary artery disease is safe and found that a single triggered intermittent imaging protocol is easier and less time consuming than dual triggering. The location of these perfusion abnormalities correlated well with thallium-201 SPECT, especially if segmental wall motion analysis and perfusion were used together.