Biomedical subjects

Guido Germano

Publications and source records attributed to Guido Germano.

7 recordsLinked to original sources

PubMed2003

Prognostic impact of hemodynamic response to adenosine in patients older than age 55 years undergoing vasodilator stress myocardial perfusion study.

BACKGROUND: The prognostic importance of various hemodynamic responses to adenosine infusion in patients undergoing adenosine stress myocardial perfusion stress (MPS) has not been defined. METHODS AND RESULTS: We identified 3444 unique patients (53.5% women, mean age 74.0+/-8.4 years) who underwent adenosine (with no additional exercise) stress myocardial perfusion single photon emission computed tomography (MPS) and were followed up for 2.0+/-0.8 years. Multivariable Cox proportional hazards analysis was used to assess the prognostic value of hemodynamic variables in predicting cardiac death (CD). Two hundred twenty-four CDs (6.5%) occurred during follow-up. By multivariable analysis, higher rest heart rate (HR) and to a lesser extent lower peak HR were markers of CD. When added to the multivariable model in place of peak and rest HR, the peak/rest HR ratio was an independent predictor of CD. Peak/rest HR ratio additionally risk-stratified patients within each MPS category. A significant interaction was found between gender and peak systolic blood pressure (SBP), in which there was an increased risk associated with a low peak SBP (<90 mm Hg at end of adenosine infusion) in men but not in women. CONCLUSIONS: Patients undergoing adenosine stress MPS with high rest HR and low peak/rest HR ratio have increased risk of CD, as do male patients with a low peak SBP. Assessment of the hemodynamic response to adenosine adds incremental prognostic value to MPS results and enhances identification of patients at risk for CD.

Adenosine↗

PubMed2003

Determinants of risk and its temporal variation in patients with normal stress myocardial perfusion scans: what is the warranty period of a normal scan?

OBJECTIVES: The aim of this study was to determine the predictors of risk and the temporal characteristics of risk associated with normal myocardial perfusion single photon emission computed tomography (MPS). BACKGROUND: No empiric data exist regarding predictors of risk after normal MPS and their temporal characteristics. METHODS: Follow-up (mean: 665 +/- 200 days, 96% complete) of 7,376 consecutive patients with normal exercise or adenosine MPS identified 78 hard events (HE) (45 cardiac deaths, 33 non-fatal myocardial infarction; 1.1% cumulative HE rate, 0.6%/year). Cox proportional hazards analysis was used to identify predictors of HE. Parametric survival analysis was used to model predicted time to HE. RESULTS: The HE rates were greater in patients with versus without previous coronary artery disease (CAD). The Cox proportional hazards model identified pharmacologic stress, known CAD, diabetes mellitus (DM), male gender, and increasing age, with interactions between stress type and previous CAD (lower risk in patients without previous CAD undergoing exercise stress vs. all others) and between DM and gender (higher risk in DM females vs. all others) as the model most predictive of HE. The highest risk subgroups had a maximal event rate of 1.4% to 1.8%/year. Parametric survival models revealed that in patients without previous CAD the level of risk was uniform with time, but in patients with known CAD, risk increased with time (e.g., risk in the first year was less than in the second year, hence, a dynamic temporal component of risk was present). CONCLUSIONS: Multiple clinical factors add incremental prognostic value in patients with normal MPS, affecting their risk and its temporal pattern, and may alter the appropriate timing of repeat testing, hence establishing the existence of a "warranty" period for normal MPS studies.

Adenosine↗

PubMed2003

Adenosine myocardial perfusion single-photon emission computed tomography in women compared with men. Impact of diabetes mellitus on incremental prognostic value and effect on patient management.

OBJECTIVES: This study was designed to assess the incremental prognostic value of adenosine stress myocardial perfusion single-photon emission computed tomography (MPS) in women versus men, and to explore the prognostic impact of diabetes mellitus. BACKGROUND: Limited data are available regarding the incremental value of adenosine stress MPS for the prediction of cardiac death in women versus men and the impact of diabetes mellitus on post-adenosine MPS outcomes. Of 6,173 consecutive patients who underwent rest thallium-201/adenosine technetium-99m sestamibi MPS, 254 (4.1%) were lost to follow-up, and 586 with early revascularization < or = 60 days after MPS were censored, leaving 2,656 women and 2,677 men. RESULTS: Women had significantly smaller adenosine stress, rest, and reversible defects than men. During 27.0 +/- 8.8 month follow-up, cardiac death rates were lower in women than men (2.0%/year vs. 2.7%/year, respectively, p < 0.05). Before and after risk adjustment, cardiac death risk increased significantly in both men and women as a function of MPS results. Multivariable models revealed that MPS results provided incremental prognostic value over pre-scan data for the prediction of cardiac death in both genders. Also, while comparative unadjusted rates of early (< or =60 days post-test) coronary angiography (17% vs. 23%) and revascularization (8% vs. 12%) were significantly lower in women (p < 0.05), after adjusting for MPS, these rates were similar in men and women. Importantly, diabetic women had a significantly greater risk of cardiac death compared with other patients. Also, after risk adjustment, patients with insulin-dependent diabetes mellitus (IDDM) had higher risk of cardiac death for any MPS result than patients with non-insulin-dependent diabetes mellitus. CONCLUSION: The findings suggest that adenosine MPS has comparable incremental value for prediction of cardiac death in women and men and that MPS is appropriately influencing subsequent invasive management decisions in both genders. Diabetic women and patients with IDDM appear to have greater risk of cardiac death than other patients for any MPS result.

Adenosine↗

PubMed2003

Left ventricular mass measured by myocardial perfusion gated SPECT. Relation to three-dimensional echocardiography.

PURPOSE: The purpose of this investigation was to determine whether left ventricular mass (LVM) assessed from myocardial perfusion gated SPECT (GSPECT) data corresponds with echocardiographic estimates, and whether mass accuracy decreases as relative myocardial wall thickness increases. MATERIALS AND METHODS: Myocardial perfusion tomograms were selected retrospectively for 37 patients, of whom 18 had Tl-201 and 19 had Tc-99m sestamibi GSPECT poststress data collections, which were subsequently processed using quantitative gated SPECT software (Cedars Sinai Medical Center, Los Angeles, CA). These patients also had clinically indicated echocardiograms for assessment of wall thickness and possible valvular involvement. In addition, LV internal diameter and posterior wall thickness were measured at end-diastole by two-dimensional guided M-mode echocardiography to assess relative myocardial wall thickness, and LVM was measured by three-dimensional echocardiography using an acoustic spatial locator device. RESULTS: LVM values were not significantly different between GSPECT and three-dimensional echocardiography (153 +/- 39 g versus 146 +/- 35 g, respectively; P = NS). GSPECT correlated significantly (r = 0.63, P < 0.0001) with three-dimensional echocardiography, with a mean difference of 7 +/- 32 g but a substantial root mean squared error of 31 g. Results were similar for similar mass ranges when subgrouped by isotope and by the presence of significant myocardial perfusion defects. Results were independent of relative myocardial wall thickness determined by two-dimensional echocardiography. The two methods yielded similar results in the highest mass range of 400 to 500 g. CONCLUSIONS: GSPECT and three-dimensional echo LVM correlated significantly, but given the large spread of statistical errors, these two techniques should not be considered interchangeable. Because gamma camera resolution is limited, GSPECT LVM should be viewed as an approximation.

Adult↗

PubMedDate not supplied

Gated fluorine 18 fluorodeoxyglucose positron emission tomography: determination of global and regional left ventricular function and myocardial tissue characterization.

BACKGROUND: Our objectives were to investigate the accuracy of global and regional left ventricular (LV) function parameters determined from gated fluorine 18 deoxyglucose (FDG) positron emission tomography (PET) and to determine whether this approach complements viability imaging data for tissue characterization. Nongated FDG-PET is a clinical standard for viability imaging, but LV function is often determined with other techniques, which increases patient burden, expenditure, and co-registration errors. Better tissue characterization may be achieved if data were acquired with one test. Methods and results Forty-eight patients with LV dysfunction (including 35 with ejection fraction [EF] </=35%) underwent perfusion/FDG imaging with gating of the FDG images and radionuclide angiography (RNA) 6 +/- 6 days apart. Regional function (wall motion/thickening) and viability pattern (normal, mismatch, nontransmural scar, and transmural scar) were determined for 301 segments. Global EFs from FDG-PET (29.3% +/- 11.5%) and RNA (31.1% +/- 10.4%) were well correlated: EF(FDG-PET) = 0.91 x EF(RNA) + 0.91 (r = 0.83, P <.00001). Regional wall motion concordance between PET and RNA with three wall motion scores was 67% with moderate agreement (kappa = 0.50, P <.001). PET viability was also determined for each segment. The relative frequency of normal motion compared with abnormal motion decreased with worsening viability classification. Of the normal segments, 96 of 139 (69%) had reduced wall motion, suggesting repetitively stunned myocardium. Segments classified as normal or mismatch had a higher frequency of normal wall thickening (65% and 52%) than wall motion (31% and 17%). No segments classified as transmural scar exhibited normal wall thickening. CONCLUSION: Gated FDG-PET accurately measures global LV function. Regional function can also be determined with reasonable accuracy. This approach also provides precise co-registration of function with metabolic information and thus improved tissue characterization of the myocardium. Gated FDG-PET has the potential to assist in optimizing management of this patient population.

Aged↗

PubMedDate not supplied

Risk stratification in patients with remote prior myocardial infarction using rest-stress myocardial perfusion SPECT: prognostic value and impact on referral to early catheterization.

BACKGROUND: Little is known about the prognostic value of myocardial perfusion single photon emission computed tomography (SPECT) in patients with remote prior myocardial infarction (MI). METHODS AND RESULTS: We identified 1413 consecutive patients with remote prior MI who underwent rest-stress myocardial perfusion SPECT. Semiquantitative visual analysis of 20 SPECT segments was used to define the summed stress, rest, and difference scores. The number of non-reversible segments was used as an index of infarct size. During follow-up (>or=1 year), 118 hard events occurred: 64 cardiac deaths (CDs) and 54 recurrent MIs. Annual CD and hard event rates increased significantly as a function of SPECT abnormality. For summed stress scores less than 4, 4 to 8, 9 to 13, and more than 13, the annual CD rates were 0.4%, 0.9%, 1.7%, and 3.5%, respectively (P =.002). Patients with small MI (<4 non-reversible segments) and no or mild ischemia (summed difference score or=4 non-reversible segments) had moderate to high annual CD rates (3.7%-6.6%) regardless of the extent of ischemia. Nuclear testing added incremental prognostic information to pre-scan information. Compared with a strategy in which all patients are referred to catheterization, a strategy that referred only those patients with a risk for CD of greater than 1% by myocardial perfusion SPECT resulted in a 41.6% cost savings. CONCLUSIONS: Myocardial perfusion SPECT adds incremental value to pre-scan information and is highly predictive and cost-efficient in the risk stratification of patients with remote prior MI. Patients with normal or mildly abnormal scan results or small MI in combination with absent or mild ischemia have a low risk for CD.

Adenosine↗

PubMedDate not supplied

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