IU Indianapolis ScholarWorks :: Browsing by Author "Sawada, Stephen G."

Browsing by Author "Sawada, Stephen G."

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Comparison of left ventriculography and coronary arteriography with positron emission tomography in assessment of myocardial viability
(Wiley, 2003-02) Bourdillon, Patrick D. V.; Von Der Lohe, Elisabeth; Lewis, Stephen J.; Sharifi, Mohsen; Burt, Robert W.; Sawada, Stephen G.; Medicine, School of Medicine
Background: Assessment of viability of myocardium after an ischemic insult is an important clinical question that affects decisions pertaining to potential revascularization. The results of contrast left ventriculograms and coronary angiography were compared to positron emission tomography (PET) in 64 patients with coronary artery disease and reduced left ventricular function. Hypothesis: The study was undertaken to determine the relative utility of the invasive studies in the assessment of viability. Methods: Right anterior oblique ventriculograms were assessed for hypokinesis, akinesis, or dyskinesis in six segments. The PET scans were assessed for viability by visual estimation of flourodeoxyglucose (FDG) uptake in six segments that corresponded to the segments analyzed on the ventriculograms. Results: Of a total of 373 segments successfully analyzed by PET, 272 were judged to be viable (normal or hypokinetic) by contrast ventriculography. Of these, 253 (93%) were considered viable by PET. Of 177 segments deemed either normal or mild‐to‐moderately hypokinetic by ventriculography, 170 (94%) were viable by PET. Of 95 severely hypokinetic segments, 83 (84%) were viable by PET. Of 79 akinetic segments, 44 (56%) were considered viable by PET. For segments that were dyskinetic and thought to be nonviable by ventriculography, 19 of 22 (86%) were also considered nonviable by PET. For 294 segments for which a determination on viability was made based on the presence of wall motion on the ventriculogram (normal, hypokinetic, or dyskinetic; not akinetic), there was excellent agreement with PET (93%; p < 0.001). In 49 patients there was akinesis in no more than one segment in either the anterior or inferior territories, indicating the potential for assessment of viability by ventriculography in at least two of three segments in each territory. Coronary anatomy was analyzed to assess whether coronary patency could help in assessing viability. Segments supplied by patent arteries were more likely to be viable by PET than segments supplied by occluded arteries (p < 0.001). Akinetic segments were more likely to be supplied by occluded arteries (56 vs. 23, 72%). Dyskinetic segments were predominantly nonviable by PET (86%) and were usually supplied by occluded arteries (77%). Conclusion: In patients in whom the assessment of viability is clinically relevant, the presence of systolic inward motion on the contrast left ventriculogram correlates well with segment viability by PET, while outward or dyskinetic movement correlates well with nonviability. Thus, the use of PET to assess viability in many patients may be unnecessary.
Dobutamine Echocardiography for Assessment of Viability in the Current Era
(Wolters Kluwer, 2019-09) Khemka, Abhishek; Sawada, Stephen G.; Medicine, School of Medicine
Purpose of review Studies from the 1990s and early 2000s documented the utility of dobutamine echocardiography for the prediction of functional recovery and prognosis with revascularization. The results of The Surgical Treatment of Ischemic Heart Failure (STICH) trial called into question the value of viability assessment using dobutamine echocardiography. The purpose of this review is to re-examine the literature on dobutamine echocardiography, put into context the STICH results, and provide insight into the current role of dobutamine echocardiography viability testing. Recent findings In contrast to the results of previous nonrandomized trials, the STICH trial showed that patients with viability defined by nuclear perfusion imaging or dobutamine echocardiography did not have improved survival with CABG compared with optimal medical therapy. Viability by dobutamine echocardiography was defined as the presence of contractile reserve in at least five segments with baseline dysfunction. The results of dobutamine echocardiography studies published before and after initiation of the STICH trial suggest that the definition of viability utilized in that trial may be suboptimal for assessment of improvement in global function and prognosis in patients undergoing revascularization. Assessment of global contractile reserve using wall motion score (WMS) or ejection fraction may be superior to utilization of a binary definition of viability confined to assessment of contractile reserve in a fixed number of segments because these indices provide information on both the magnitude and extent of contractile reserve of the entire left ventricle (LV). Summary Assessment of WMS or ejection fraction with dobutamine echocardiography may be the optimal means of evaluating the impact of viability on prognosis. Video abstract http://links.lww.com/HCO/A56
Evaluation of the anti-ischemic effects of D-ribose during dobutamine stress echocardiography: a pilot study
(BioMed Central, 2009-02-07) Sawada, Stephen G.; Lewis, Stephen; Kovacs, Roxanne; Khouri, Samer; Gradus-Pizlo, Irmina; St Cyr, John A.; Feigenbaum, Harvey; Medicine, School of Medicine
D-Ribose, a pentose sugar, has shown to improve myocardial high-energy phosphate stores depleted by ischemia. This study investigated the ability of D-Ribose with low dose dobutamine to improve the contractile response of viable myocardium to dobutamine and to assess the efficacy of D-ribose in reducing stress-induced ischemia. Twenty-six patients with ischemic cardiomyopathy completed a two-day, randomized, double blind crossover trial comparing the effects of D-Ribose and placebo on regional wall motion. On the first study day, either D-Ribose or placebo was infused for 4.5 hours. Low (5 and 10 μ/kg/min) and subsequently, high (up to 50 μ/kg/min) dose dobutamine echocardiography was then performed. On the second study day, patients crossed over to the alternative article for a similar 4.5 hours infusion time period and underwent a similar evaluation. The wall motion response during low dose dobutamine was the same with D-Ribose and placebo in 77% of segments (203/263, Kappa = 0.37). In segments with discordant responses, more segments improved with D-Ribose than with placebo (41 vs. 19 segments, p = 0.006). With high dose dobutamine infusion, the wall motion response (ischemia vs. no ischemia) was the same with D-Ribose and placebo in 83% of interpretable segments (301/363, kappa = 0.244). In segments with discordant responses, there were more ischemic segments with placebo compared to D-Ribose (36 vs. 26, p = 0.253). Nineteen patients developed ischemia during the dobutamine and placebo infusion and 13 patients had ischemia during dobutamine and D-ribose infusion (p = 0.109). D-Ribose improved contractile responses to dobutamine in viable myocardium with resting dysfunction but had no significant effect in reducing the frequency of stress-induced wall motion abnormalities.
Mitral Annular Plane Systolic Excursion: An Early Marker of Mortality in Severe COVID-19 Infection
(Elsevier, 2020-08-18) Jarori, Upasana; Maatman, Thomas K.; Maatman, Benjamin; Mastouri, Ronald; Sawada, Stephen G.; Khemka, Abhishek; Medicine, School of Medicine
Respiratory failure is a major cause of mortality among hospitalized patients with COVID-19. Previous studies have shown that right ventricular (RV) dilation and reduced RV longitudinal strain are markers of poor outcome in this disease. COVID-19 can cause direct myocardial injury resulting in left ventricular (LV) systolic dysfunction and heart failure suggesting that assessment of LV function might also have prognostic value. Reduction of longitudinal systolic function assessed by mitral annular plane systolic excursion (MAPSE) is an early indicator of myocardial disease in various cardiac disorders. In this retrospective study, we investigated the prognostic value of MAPSE in patients admitted with respiratory failure related to COVID-19 infection.
Prognostic utility of blood pressure-adjusted global and basal systolic longitudinal strain
(Bioscientifica, 2016-03) Rhea, Isaac B.; Rehman, Shuja; Jarori, Upasana; Choudhry, Muhammad W.; Feigenbaum, Harvey; Sawada, Stephen G.; Department of Medicine, IU School of Medicine
Assessment of global longitudinal systolic strain (GLS) and longitudinal systolic strain of the basal segments (BLS) has shown prognostic value in cardiac disorders. However, strain is reduced with increased afterload. We assessed the prognostic value of GLS and BLS adjusted for afterload. GLS and BLS were determined in 272 subjects with normal ejection fraction and no known coronary disease, or significant valve disease. Systolic blood pressure (SP) and diastolic blood pressure (DP) obtained at the time of echocardiography were used to adjust GLS and BLS as follows: strain×SP (mmHg)/120 mmHg and strain×DP (mmHg)/80 mmHg. Patients were followed for cardiac events and mortality. The mean age was 53±15 years and 53% had hypertension. There were 19 cardiac events and 70 deaths over a mean follow-up of 26±14 months. Cox analysis showed that left ventricular mass index (P=0.001), BLS (P<0.001), and DP-adjusted BLS (P<0.001) were independent predictors of cardiac events. DP-adjusted BLS added incremental value (P<0.001) to the other two predictors and had an area under the curve of 0.838 for events. DP (P=0.001), age (P=0.001), ACE inhibitor use (P=0.017), and SP-adjusted BLS (P=0.012) were independent predictors of mortality. SP-adjusted BLS added incremental value (P=0.014) to the other independent predictors. In conclusion, DP-adjusted BLS and SP-adjusted BLS were independent predictors of cardiac events and mortality, respectively. Blood pressure-adjusted strain added incremental prognostic value to other predictors of outcome.
Prognostic value of left atrial size in hypertensive African Americans undergoing stress echocardiography
(Baishideng Publishing Group, 2021) Khemka, Abhishek; Sutter, David A.; Habhab, Mazin N.; Thomaides, Athanasios; Hornsby, Kyle; Feigenbaum, Harvey; Sawada, Stephen G.; Medicine, School of Medicine
Background: Left atrial (LA) enlargement is a marker of increased risk in the general population undergoing stress echocardiography. African American (AA) patients with hypertension are known to have less atrial remodeling than whites with hypertension. The prognostic impact of LA enlargement in AA with hypertension undergoing stress echocardiography is uncertain. Aim: To investigate the prognostic value of LA size in hypertensive AA patients undergoing stress echocardiography. Methods: This retrospective outcomes study enrolled 583 consecutive hypertensive AA patients who underwent stress echocardiography over a 2.5-year period. Clinical characteristics including cardiovascular risk factors, stress and echocardiographic data were collected from the electronic health record of a large community hospital. Treadmill exercise and Dobutamine protocols were conducted based on standard practices. Patients were followed for all-cause mortality. The optimal cutoff value of antero-posterior LA diameter for mortality was assessed by receiver operating characteristic analysis. Cox regression was used to determine variables associated with outcome. Results: The mean age was 57 ± 12 years. LA dilatation was present in 9% (54) of patients (LA anteroposterior ≥ 2.4 cm/m2). There were 85 deaths (15%) during 4.5 ± 1.7 years of follow-up. LA diameter indexed for body surface area had an area under the curve of 0.72 ± 0.03 (optimal cut-point of 2.05 cm/m2). Variables independently associated with mortality included age [P = 0.004, hazard ratio (HR) 1.34 (1.10-1.64)], tobacco use [P = 0.001, HR 2.59 (1.51-4.44)], left ventricular hypertrophy [P = 0.001 , HR 2.14 (1.35-3.39)], Dobutamine stress [P = 0.003, HR 2.12 (1.29-3.47)], heart failure history [P = 0.031, HR 1.76 (1.05-2.94)], LA diameter ≥ 2.05 cm/m2 [P = 0.027, HR 1.73 (1.06-2.82)], and an abnormal stress echocardiogram [P = 0.033, HR 1.67 (1.04-2.68)]. LA diameter as a continuous variable was also independently associated with mortality but LA size ≥ 2.40 cm/m2 was not. Conclusion: LA enlargement is infrequent in hypertensive AA patients when traditional reference values are used. LA enlargement is independently associated with mortality when a lower than "normal" threshold (≥ 2.05 cm/m2) is used.
Safety and feasibility of dopamine-atropine stress echocardiography
(Wiley, 2021-04) Khemka, Abhishek; Rao, Roopa; Ghumman, Waqas; Mahenthiran, Jothiharan; Feigenbaum, Harvey; Sawada, Stephen G.; Medicine, School of Medicine
Background Dobutamine-atropine stress echocardiography (DSE) has lower sensitivity in patients with advanced liver disease (ALD) due to vasodilation. Hypothesis Dopamine-atropine stress echocardiography (DopSE) may be an alternative to DSE in ALD patients by improving the blood pressure response to stress. Methods The safety and tolerability of DSE and DopSE were compared in 10 volunteers. The safety, adverse effects, and efficacy of DopSE were then assessed in 105 patients, 98 of whom had ALD. Dopamine was infused in stepwise fashion from 5 µg/kg/min to a peak dose of 40 µg/kg/min. Atropine was given before and in early stages of dopamine infusion up to cumulative dose of 1.5 mg. The hemodynamic responses of 98 ALD patients were compared with 102 patients with ALD who underwent standard DSE. Results In normal volunteers, systolic BP increased more with DopSE compared to DSE (61 ± 19 mm Hg vs 39 ± 15 mm Hg, P = .008). In 105 patients who underwent DopSE, none had adverse effects that required early stress termination. In the groups with ALD, the systolic BP increase (38 ± 28 mm Hg vs 12 ± 27 mm Hg, P < .001) and peak rate pressure product (RPP) (22 861 ± 5289 vs 17 211 ± 3848, P = <.001) were both higher in those undergoing DopSE versus DSE. The sensitivity and specificity of DopSE were 45% and 88%, respectively for coronary disease (≥70% stenosis) in 37 patients who had angiography. Conclusions Dopamine-atropine stress echocardiography appears to be a safe stress modality and provides greater increases in RPP in patients with ALD compared to DSE.
Sex Differences in Stress-Induced (Takotsubo) Cardiomyopathy
(Elsevier, 2022-11-18) Maskoun, Waddah; Alqam, Bilal; Habash, Fuad; Gheith, Zaid; Sawada, Stephen G.; Vallurupalli, Srikanth; Medicine, School of Medicine
Background: Takotsubo cardiomyopathy (TC) affects predominantly women. Prior studies have suggested that men might have worse short-term outcomes, but limited data are available regarding long-term outcomes. We hypothesized that men, compared to women, with TC have worse short- and long-term outcomes. Methods: A retrospective study of patients diagnosed with TC between 2005 and 2018 in the Veteran Affairs system was performed. Primary outcomes were in-hospital death, 30-day risk of stroke, death, and long-term mortality. Results: A total of 641 patients were included (444 men [69%]; 197 women [31%]). Men had a higher median age (65 vs 60 years; P < 0.001), and women were more likely to present with chest pain (68.7% vs 44.1%; P < 0.001). Physical triggers were more common in men (68.7% vs 44.1%, P < 0.001). Men had a higher in-hospital mortality rate (8.1% vs 1%; P < 0.001). On multivariable regression analysis, female sex was an independent predictor for improved in-hospital mortality, compared to men (odds ratio 0.25, 95% confidence interval 0.06-1.10; P = 0.04). On 30-day follow-up, no difference occurred in a combined outcome of stroke and death (3.9% vs 1.5%; P = 0.12). On long-term follow-up (3.7 ± 3.1 years), female sex was identified as an independent predictor of lower mortality (hazard ratio 0.71, 95% CI 0.51-0.97; P = 0.032). Women were more likely to have TC recurrence (3.6% vs 1.1%; P = 0.04). Conclusions: In our study with a predominantly male population, men had less-favourable short- and long-term outcomes after TC, compared to those of women.
Wall motion abnormalities with low-dose dobutamine predict a high risk of cardiac death in medically treated patients with ischemic cardiomyopathy
(Wiley, 2009-07) Maskoun, Waddah; Mustafa, Nowwar; Mahenthiran, Jothiharan; Gradus‐Pizlo, Irmina; Kamalesh, Masoor; Feigenbaum, Harvey; Sawada, Stephen G.; Medicine, School of Medicine
BACKGROUND: Severe and extensive coronary artery disease is the underlying cause of stress-induced wall motion abnormalities (SWMA) with low-dose (10 microg/kg/min) dobutamine suggesting that these abnormalities may identify those with poor outcome. HYPOTHESIS: We assessed the prognostic value of low-dose SWMA in medically treated patients with ischemic cardiomyopathy. METHODS: Low- and peak-dose dobutamine echocardiography was performed in 235 patients with ischemic cardiomyopathy (ejection fraction 31% +/- 8%) who were treated with medical therapy. The survival of patients with low-dose SWMA (n = 33) was compared with the survival of patients without ischemia (n = 85) and those with peak-dose SWMA (n = 117). RESULTS: There were 123 cardiac deaths (52%) during follow-up of 4.1 +/- 3.3 years. Multivariate predictors of cardiac death were age (p = 0.002, hazard ratio [HR]: 1.03), diabetes (p = 0.028, HR: 1.54), New York Heart Association (NYHA) class III, IV heart failure (p = 0.001, HR: 1.94), the presence of peak dose SWMA (p < 0.001, HR: 2.59), and low-dose SWMA (p = 0.005, HR: 2.28). Survival of patients without ischemia was significantly better than those with peak-dose SWMA (p < 0.0001) and those with low-dose SWMA (p = 0.001). The survival of patients with low-dose SWMA was the same as those with peak-dose SWMA (p = 0.89). CONCLUSIONS: Low-dose SWMA is an independent predictor of cardiac mortality in medically treated patients with ischemic cardiomyopathy. Patients with low-dose SWMA are at equivalent risk to those with peak-dose SWMA.

Browsing by Author "Sawada, Stephen G."

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