Thomas P. Rocco

Comparison of thallium redistribution with rest “reinjection” imaging for the detection of viable myocardium

To determine the incidence of incomplete redistribution on conventional delayed thallium images, 41 patients with persistent perfusion defects on myocardial images recorded 3 to 4 hours after thallium injection during exercise were studied. At the conclusion of their delayed images the patients were reinjected at rest with approximately 1 mCi of thallium-201 and a third set of images was recorded. The images were presented at random in pairs (initial:delayed, initial:reinjection) to 2 experienced observers for qualitative scoring of 9 segments/patient. Of the 360 segments analyzed, concordance between the delayed and reinjected images occurred in 307 (85%). Of 141 segments that demonstrated a persistent perfusion abnormality on 3- to 4-hour delayed images, 44 (31%) were reassigned to a redistribution score after reinjection. In 9 patients, reinjection images provided the only evidence of ischemia from the scintigraphic data. In 13 of 14 vascular territories that demonstrated redistribution after reinjection, intact perfusion (either anterograde or via collaterals) was detected at coronary angiography. These data suggest that rest reinjection imaging may provide a means of detecting viable myocardium in segments that demonstrate a fixed perfusion abnormality on conventional 3- to 4-hour delayed thallium images.

Technetium-99m isonitrile myocardial uptake at rest. II. Relation to clinical markers of potential viability☆

To determine the utility of rest-injected technetium-99m methoxybutyl isonitrile (Tc-99m isonitrile) uptake as a marker of myocardial viability, the regional uptake of this agent was compared with regional wall motion by equilibrium gated blood pool scan in 26 patients with previous myocardial infarction and with postrevascularization uptake in 8 patients after coronary bypass surgery. Rest left ventricular Tc-99m isonitrile uptake was assessed qualitatively in three coronary vascular territories as grade 0 (markedly reduced) to grade 2 (normal), and quantitatively by circumferential profile analysis. Wall motion was scored qualitatively in corresponding vascular territories as normal, hypokinetic or akinetic/dyskinetic. There was an overall relation between qualitative Tc-99m isonitrile uptake and wall motion. Abnormal wall motion occurred in 74% of vascular territories with perfusion grade 0, in 61% of those with grade 1 and in 30% of those with grade 2; however, 26% of territories with grade 0 uptake had normal wall motion. In the territories visually assigned perfusion grade 0, quantitative isonitrile uptake (mean value +/- SD) was higher when corresponding wall motion was normal or hypokinetic (62 +/- 15%) than when akinesia was detected by gated blood pool scan (39 +/- 16%, p less than 0.02). Qualitative Tc-99m isonitrile uptake improved after coronary bypass surgery in 12 of 13 territories with reduced uptake preoperatively; this included all 5 territories with a preoperative Tc-99m isonitrile score of 0. Quantitative uptake in these regions increased from 55 +/- 18% to 73 +/- 21% (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Noninvasive assessment of transplant-associated arteriosclerosis

BACKGROUND Transplant-associated arteriosclerosis is the major limitation to long-term survival in the cardiac transplant recipient, and annual surveillance angiography is used in many centers to monitor its progression. Noninvasive methods would be preferable because angiography is invasive, costly, and insensitive; however, the reliability of such methods has been questioned. METHODS All publications relating to the assessment of the cardiac allograft by noninvasive testing were identified through MEDLINE and a review of references from the published literature on transplant-associated arteriosclerosis. RESULTS Resting and stress ECG, radionuclide scintigraphy, echocardiography, and positron emission tomography have all been used in cardiac transplant recipients with variable results. Most techniques are insensitive, but this limitation may be improved with pharmacologic stress imaging like dobutamine echocardiography. Although insensitive, some methods have good specificity (i.e., radionuclide scintigraphy). The noninvasive measurement of absolute coronary blood flow is promising as a specific and sensitive technique but is limited by availability and cost. CONCLUSIONS In general, noninvasive techniques to assess transplant-associated coronary arteriosclerosis are limited by variable sensitivity and specificity. However, certain methods, such as dobutamine echocardiography and radionuclide scintigraphy, can provide important adjunctive physiologic information to angiography. Such techniques can therefore help to guide the care and treatment of the cardiac transplant recipient with allograft coronary arteriosclerosis.

Technetium-99m isonitrile myocardial uptake at rest. I. Relation to severity of coronary artery stenosis

To determine the potential of planar technetium-99m methoxybutyl isonitrile myocardial imaging as a method of detecting totally occluded or severely stenosed coronary arteries, the regional distribution of technetium-99m isonitrile at rest was compared with the coronary anatomy in 38 patients with prior myocardial infarction who underwent coronary arteriography. Left ventricular technetium-99m isonitrile tracer uptake at rest was assessed in the three major coronary vascular territories. When qualitative rest technetium-99m isonitrile uptake was markedly reduced or absent (grade 0), there was a 91% probability of finding a totally occluded or severely stenosed coronary artery. When qualitative tracer uptake was reduced (grade 1) or normal (grade 2), it excluded all territories supplied by a totally occluded vessel with poor collateral flow. Quantitative technetium-99m isonitrile uptake (mean +/- 1 standard deviation) in territories supplied by an occluded coronary artery with poor collateral flow (42 +/- 21%) was lower than in territories supplied by a vessel with less than 50% stenosis (87 +/- 10%) and 50 to 99% stenosis (74 +/- 19%) (p less than 0.001). Furthermore, technetium-99m isonitrile uptake in areas supplied by an occluded coronary artery with good collateral flow (61 +/- 23%) was lower than in areas supplied by a vessel with less than 50% stenosis (87 +/- 10%) (p less than 0.001). Because rest technetium-99m isonitrile imaging detects coronary occlusion with poor collateral flow, this method may be useful in assessing patients with acute myocardial infarction.

Clinical Profile and Underdiagnosis of Pulmonary Hypertension in US Veteran Patients

Pulmonary hypertension (PH) is the principal intermediate pathophenotype responsible for right-sided congestive heart failure.1 When present, even subclinical pathological changes to cardiovascular function mediated by untreated PH are associated with increased morbidity and decreased longevity.2 Observations from epidemiological reports have indicated that compared with other community-based populations, the U.S. military Veteran patient population has an increased prevalence of PH-associated primary lung and cardiovascular disease;3 however, the epidemiology of PH for this population is not known. In the current study, we leveraged the unique strengths of the VA clinical database, which is a universal and centralized electronic medical record, to test our hypothesis that PH is a prevalent form of cardiovascular disease in a cohort of Veteran patients. We further aimed to investigate the clinical profile and diagnostic strategies used for PH in this patient population.Background—Pulmonary hypertension (PH) is a key contributor to cardiovascular morbidity and early mortality; however, reports are lacking on the epidemiology of PH in at-risk patient populations. Methods and Results—The echocardiography registries from 2 major Veterans Affairs hospitals were accessed to identify patients with at least moderate PH, defined here as a pulmonary artery systolic pressure ≥60 mm Hg detected echocardiographically. From a total of 10 471 individual patient transthoracic echocardiograms, we identified moderate or severe PH in 340 patients (332 men; mean, 77 years; mean pulmonary artery systolic pressure, 69.4±10.5 mm Hg), of which PH was listed as a diagnosis in the medical record for only 59 (17.3%). At a mean of 832 days (0–4817 days) following echocardiography diagnosing PH, 150 (44.1%) patients were deceased. PH was present without substantial left heart remodeling: the mean left ventricular ejection fraction was 0.50±0.16, left ventricular end-diastolic dimension was 5.0±0.9 cm, and left atrial dimension was 4.4±0.7 cm. Cardiac catheterization (n=122, 36%) demonstrated a mean pulmonary artery pressure of 40.5±11.4 mm Hg, pulmonary capillary wedge pressure of 22.6±8.9 mm Hg, and pulmonary vascular resistance of 4.6±2.9 Wood units. Diagnostic strategies for PH were variable and often incomplete; for example, only 16% of appropriate patients were assessed with a nuclear ventilation/perfusion scan for thromboembolic causes of PH. Conclusions—In an at-risk patient population, PH is underdiagnosed and associated with substantial mortality. Enhanced awareness is necessary among practitioners regarding contemporary PH diagnostic strategies.

Evaluation of left ventricular diastolic function using an ambulatory radionuclide monitor: Relationship to left ventricular systolic performance

Abnormalities of left ventricular (LV) filling may occur prior to systolic dysfunction in patients with both coronary and noncoronary heart disease. To determine the incidence of diastolic dysfunction and to assess the relationship of such dysfunction to systolic performance, we measured systolic and diastolic function at rest in a series of healthy volunteers (n = 10) and in patients with cardiovascular disease (n = 42). Twenty patients had coronary artery disease (CAD) with prior myocardial infarction, six patients had CAD without myocardial infarction, and the remaining 16 patients had a variety of noncoronary heart diseases, including valvular heart disease, dilated cardiomyopathy, and hypertensive disease. The 42 patients manifested a wide variation in LV systolic function (ejection fractions ranged from 6% to 65%). Patients with reduced LV ejection fraction (EF) manifested a reduction in cardiac output and peak ejection rate proportionate to the reduction in EF. Diastolic function showed a fall in LV peak (PFR) and average (AFR) filling rates; these were reduced in proportion to the fall in EF. Heart rate was an insensitive index of the magnitude of impairment of LV systolic function. These data suggest that measurements of diastolic function do not provide additional information in patients with impaired systolic function.

Clinical Profile and Underdiagnosis of Pulmonary Hypertension in US Veteran PatientsClinical Perspective

Pulmonary hypertension (PH) is the principal intermediate pathophenotype responsible for right-sided congestive heart failure.1 When present, even subclinical pathological changes to cardiovascular function mediated by untreated PH are associated with increased morbidity and decreased longevity.2 Observations from epidemiological reports have indicated that compared with other community-based populations, the U.S. military Veteran patient population has an increased prevalence of PH-associated primary lung and cardiovascular disease;3 however, the epidemiology of PH for this population is not known. In the current study, we leveraged the unique strengths of the VA clinical database, which is a universal and centralized electronic medical record, to test our hypothesis that PH is a prevalent form of cardiovascular disease in a cohort of Veteran patients. We further aimed to investigate the clinical profile and diagnostic strategies used for PH in this patient population.Background—Pulmonary hypertension (PH) is a key contributor to cardiovascular morbidity and early mortality; however, reports are lacking on the epidemiology of PH in at-risk patient populations. Methods and Results—The echocardiography registries from 2 major Veterans Affairs hospitals were accessed to identify patients with at least moderate PH, defined here as a pulmonary artery systolic pressure ≥60 mm Hg detected echocardiographically. From a total of 10 471 individual patient transthoracic echocardiograms, we identified moderate or severe PH in 340 patients (332 men; mean, 77 years; mean pulmonary artery systolic pressure, 69.4±10.5 mm Hg), of which PH was listed as a diagnosis in the medical record for only 59 (17.3%). At a mean of 832 days (0–4817 days) following echocardiography diagnosing PH, 150 (44.1%) patients were deceased. PH was present without substantial left heart remodeling: the mean left ventricular ejection fraction was 0.50±0.16, left ventricular end-diastolic dimension was 5.0±0.9 cm, and left atrial dimension was 4.4±0.7 cm. Cardiac catheterization (n=122, 36%) demonstrated a mean pulmonary artery pressure of 40.5±11.4 mm Hg, pulmonary capillary wedge pressure of 22.6±8.9 mm Hg, and pulmonary vascular resistance of 4.6±2.9 Wood units. Diagnostic strategies for PH were variable and often incomplete; for example, only 16% of appropriate patients were assessed with a nuclear ventilation/perfusion scan for thromboembolic causes of PH. Conclusions—In an at-risk patient population, PH is underdiagnosed and associated with substantial mortality. Enhanced awareness is necessary among practitioners regarding contemporary PH diagnostic strategies.

The Clinical Profile and Under-Diagnosis of Pulmonary Hypertension in U.S. Veteran Patients

Pulmonary hypertension (PH) is the principal intermediate pathophenotype responsible for right-sided congestive heart failure.1 When present, even subclinical pathological changes to cardiovascular function mediated by untreated PH are associated with increased morbidity and decreased longevity.2 Observations from epidemiological reports have indicated that compared with other community-based populations, the U.S. military Veteran patient population has an increased prevalence of PH-associated primary lung and cardiovascular disease;3 however, the epidemiology of PH for this population is not known. In the current study, we leveraged the unique strengths of the VA clinical database, which is a universal and centralized electronic medical record, to test our hypothesis that PH is a prevalent form of cardiovascular disease in a cohort of Veteran patients. We further aimed to investigate the clinical profile and diagnostic strategies used for PH in this patient population.Background—Pulmonary hypertension (PH) is a key contributor to cardiovascular morbidity and early mortality; however, reports are lacking on the epidemiology of PH in at-risk patient populations. Methods and Results—The echocardiography registries from 2 major Veterans Affairs hospitals were accessed to identify patients with at least moderate PH, defined here as a pulmonary artery systolic pressure ≥60 mm Hg detected echocardiographically. From a total of 10 471 individual patient transthoracic echocardiograms, we identified moderate or severe PH in 340 patients (332 men; mean, 77 years; mean pulmonary artery systolic pressure, 69.4±10.5 mm Hg), of which PH was listed as a diagnosis in the medical record for only 59 (17.3%). At a mean of 832 days (0–4817 days) following echocardiography diagnosing PH, 150 (44.1%) patients were deceased. PH was present without substantial left heart remodeling: the mean left ventricular ejection fraction was 0.50±0.16, left ventricular end-diastolic dimension was 5.0±0.9 cm, and left atrial dimension was 4.4±0.7 cm. Cardiac catheterization (n=122, 36%) demonstrated a mean pulmonary artery pressure of 40.5±11.4 mm Hg, pulmonary capillary wedge pressure of 22.6±8.9 mm Hg, and pulmonary vascular resistance of 4.6±2.9 Wood units. Diagnostic strategies for PH were variable and often incomplete; for example, only 16% of appropriate patients were assessed with a nuclear ventilation/perfusion scan for thromboembolic causes of PH. Conclusions—In an at-risk patient population, PH is underdiagnosed and associated with substantial mortality. Enhanced awareness is necessary among practitioners regarding contemporary PH diagnostic strategies.

The Clinical Profile and Under-Diagnosis of Pulmonary Hypertension in U.S. Veteran Patients: Maron et al: Severe Pulmonary Hypertension Is Under-Diagnosed

Pulmonary hypertension (PH) is the principal intermediate pathophenotype responsible for right-sided congestive heart failure.1 When present, even subclinical pathological changes to cardiovascular function mediated by untreated PH are associated with increased morbidity and decreased longevity.2 Observations from epidemiological reports have indicated that compared with other community-based populations, the U.S. military Veteran patient population has an increased prevalence of PH-associated primary lung and cardiovascular disease;3 however, the epidemiology of PH for this population is not known. In the current study, we leveraged the unique strengths of the VA clinical database, which is a universal and centralized electronic medical record, to test our hypothesis that PH is a prevalent form of cardiovascular disease in a cohort of Veteran patients. We further aimed to investigate the clinical profile and diagnostic strategies used for PH in this patient population.Background—Pulmonary hypertension (PH) is a key contributor to cardiovascular morbidity and early mortality; however, reports are lacking on the epidemiology of PH in at-risk patient populations. Methods and Results—The echocardiography registries from 2 major Veterans Affairs hospitals were accessed to identify patients with at least moderate PH, defined here as a pulmonary artery systolic pressure ≥60 mm Hg detected echocardiographically. From a total of 10 471 individual patient transthoracic echocardiograms, we identified moderate or severe PH in 340 patients (332 men; mean, 77 years; mean pulmonary artery systolic pressure, 69.4±10.5 mm Hg), of which PH was listed as a diagnosis in the medical record for only 59 (17.3%). At a mean of 832 days (0–4817 days) following echocardiography diagnosing PH, 150 (44.1%) patients were deceased. PH was present without substantial left heart remodeling: the mean left ventricular ejection fraction was 0.50±0.16, left ventricular end-diastolic dimension was 5.0±0.9 cm, and left atrial dimension was 4.4±0.7 cm. Cardiac catheterization (n=122, 36%) demonstrated a mean pulmonary artery pressure of 40.5±11.4 mm Hg, pulmonary capillary wedge pressure of 22.6±8.9 mm Hg, and pulmonary vascular resistance of 4.6±2.9 Wood units. Diagnostic strategies for PH were variable and often incomplete; for example, only 16% of appropriate patients were assessed with a nuclear ventilation/perfusion scan for thromboembolic causes of PH. Conclusions—In an at-risk patient population, PH is underdiagnosed and associated with substantial mortality. Enhanced awareness is necessary among practitioners regarding contemporary PH diagnostic strategies.