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Mechanism of decreased sensitivity of dobutamine associated left ventricular wall motion analyses for appreciating inducible ischemia in older adults.

Vasu S, Little WC, Morgan TM, Stacey RB, Ntim WO, Hamilton C, Thohan V, Chiles C, Hundley WG - J Cardiovasc Magn Reson (2015)

Bottom Line: Dobutamine associated left ventricular (LV) wall motion analyses exhibit reduced sensitivity for detecting inducible ischemia in individuals with increased LV wall thickness.This study was performed to better understand the mechanism of this reduced sensitivity in the elderly who often manifest increased LV wall thickness and risk factors for coronary artery disease.These findings provide insight as to why dobutamine associated wall motion analyses exhibit reduced sensitivity for identifying inducible ischemia in elderly.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal medicine, Section on Cardiology, Wake Forest School of Medicine, Winston Salem, North Carolina, 27157, USA. svasu@wakehealth.edu.

ABSTRACT

Background: Dobutamine associated left ventricular (LV) wall motion analyses exhibit reduced sensitivity for detecting inducible ischemia in individuals with increased LV wall thickness. This study was performed to better understand the mechanism of this reduced sensitivity in the elderly who often manifest increased LV wall thickness and risk factors for coronary artery disease.

Methods: During dobutamine cardiovascular magnetic resonance (DCMR) stress testing, we assessed rate pressure product (RPP), aortic pulse wave velocity (PWV), LV myocardial oxygen demand (pressure volume area, PVA, mass, volumes, concentricity, and the presence of wall motion abnormalities (WMA) and first pass gadolinium enhanced perfusion defects (PDs) indicative of ischemia in 278 consecutively recruited individuals aged 69 ± 8 years with pre-existing or known risk factors for coronary artery disease. Each variable was assessed independently by personnel blinded to participant identifiers and analyses of other DCMR or hemodynamic variables.

Results: Participants were 80% white, 90% hypertensive, 43% diabetic and 55% men. With dobutamine, 60% of the participants who exhibited PDs had no inducible WMA. Among these participants, myocardial oxygen demand was lower than that observed in those who had both wall motion and perfusion abnormalities suggestive of ischemia (p = 0.03). Relative to those with PDs and inducible WMAs, myocardial oxygen demand remained different in these individuals with PDs without an inducible WMA after accounting for LV afterload and contractility (p = 0.02 and 0.03 respectively), but not after accounting for either LV stress related end diastolic volume index (LV preload) or resting concentricity (p = 0.31-0.71).

Conclusions: During dobutamine stress testing, elderly patients experience increased LV concentricity and declines in LV preload and myocardial oxygen demand, all of which are associated with an absence of inducible LV WMAs indicative of myocardial ischemia. These findings provide insight as to why dobutamine associated wall motion analyses exhibit reduced sensitivity for identifying inducible ischemia in elderly.

Trial registration: This study was registered with Clinicaltrials.gov (NCT00542503).

No MeSH data available.


Related in: MedlinePlus

Resting measures of myocardial oxygen demand between the three groups. The mean ± the standard error of the myocardial oxygen demand (Y-axis) and the number of participants in each of the 3 study groups (X-axis) are shown. The myocardial stroke work is denoted by the gray bars, and the pressure volume area is denoted by the black bars. At rest, Group II participants (wall motion negative, perfusion positive) have lower myocardial oxygen demand as assessed by myocardial stroke work (SW) than those in III (wall motion and perfusion positive) or Group I. Also, PVA is reduced in Groups II relative to Group I and trends toward a difference with Group III.
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Fig3: Resting measures of myocardial oxygen demand between the three groups. The mean ± the standard error of the myocardial oxygen demand (Y-axis) and the number of participants in each of the 3 study groups (X-axis) are shown. The myocardial stroke work is denoted by the gray bars, and the pressure volume area is denoted by the black bars. At rest, Group II participants (wall motion negative, perfusion positive) have lower myocardial oxygen demand as assessed by myocardial stroke work (SW) than those in III (wall motion and perfusion positive) or Group I. Also, PVA is reduced in Groups II relative to Group I and trends toward a difference with Group III.

Mentions: The indices of myocardial oxygen demand at rest are shown in Figure 3 and at stress in Figure 4. At rest as shown in Figure 3, the left ventricular pressure volume area (PVA) and stroke work (SW) of individuals in Group II were lower than those in Group I (9,016 ± 559 vs. 10,439 ± 201 mmHg*ml, p = 0.02 and 6,594 ± 417 vs. 7,794 ± 150 mmHg*ml, p = 0.007 respectively) and lower than those in Group III (9016 ± 559 vs. 10,618 ± 768 mmHg*ml, p = 0.09 and 6,594 ± 417 vs. 7708 ± 569 mmHg*ml, p = 0.01 respectively). However there were no differences in PVA and SW between Groups I and II with dobutamine (7,660 ± 645 vs. 8,409 ± 227 mmHg*ml, p = 0.27 and 6,160 ± 524 vs. 6,877 ± 187 mmHg*ml, p = 0.25 respectively). In contrast, during stress, the PVA and SW in Group II were lower when compared to Group III (7660 ± 645 vs. 10,023 ± 862 mmHg*ml, p = 0.03, and 6,160 ± 524 vs. 7682 ± 715 mmHg*ml, p = 0.09), respectively.Figure 3


Mechanism of decreased sensitivity of dobutamine associated left ventricular wall motion analyses for appreciating inducible ischemia in older adults.

Vasu S, Little WC, Morgan TM, Stacey RB, Ntim WO, Hamilton C, Thohan V, Chiles C, Hundley WG - J Cardiovasc Magn Reson (2015)

Resting measures of myocardial oxygen demand between the three groups. The mean ± the standard error of the myocardial oxygen demand (Y-axis) and the number of participants in each of the 3 study groups (X-axis) are shown. The myocardial stroke work is denoted by the gray bars, and the pressure volume area is denoted by the black bars. At rest, Group II participants (wall motion negative, perfusion positive) have lower myocardial oxygen demand as assessed by myocardial stroke work (SW) than those in III (wall motion and perfusion positive) or Group I. Also, PVA is reduced in Groups II relative to Group I and trends toward a difference with Group III.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4389511&req=5

Fig3: Resting measures of myocardial oxygen demand between the three groups. The mean ± the standard error of the myocardial oxygen demand (Y-axis) and the number of participants in each of the 3 study groups (X-axis) are shown. The myocardial stroke work is denoted by the gray bars, and the pressure volume area is denoted by the black bars. At rest, Group II participants (wall motion negative, perfusion positive) have lower myocardial oxygen demand as assessed by myocardial stroke work (SW) than those in III (wall motion and perfusion positive) or Group I. Also, PVA is reduced in Groups II relative to Group I and trends toward a difference with Group III.
Mentions: The indices of myocardial oxygen demand at rest are shown in Figure 3 and at stress in Figure 4. At rest as shown in Figure 3, the left ventricular pressure volume area (PVA) and stroke work (SW) of individuals in Group II were lower than those in Group I (9,016 ± 559 vs. 10,439 ± 201 mmHg*ml, p = 0.02 and 6,594 ± 417 vs. 7,794 ± 150 mmHg*ml, p = 0.007 respectively) and lower than those in Group III (9016 ± 559 vs. 10,618 ± 768 mmHg*ml, p = 0.09 and 6,594 ± 417 vs. 7708 ± 569 mmHg*ml, p = 0.01 respectively). However there were no differences in PVA and SW between Groups I and II with dobutamine (7,660 ± 645 vs. 8,409 ± 227 mmHg*ml, p = 0.27 and 6,160 ± 524 vs. 6,877 ± 187 mmHg*ml, p = 0.25 respectively). In contrast, during stress, the PVA and SW in Group II were lower when compared to Group III (7660 ± 645 vs. 10,023 ± 862 mmHg*ml, p = 0.03, and 6,160 ± 524 vs. 7682 ± 715 mmHg*ml, p = 0.09), respectively.Figure 3

Bottom Line: Dobutamine associated left ventricular (LV) wall motion analyses exhibit reduced sensitivity for detecting inducible ischemia in individuals with increased LV wall thickness.This study was performed to better understand the mechanism of this reduced sensitivity in the elderly who often manifest increased LV wall thickness and risk factors for coronary artery disease.These findings provide insight as to why dobutamine associated wall motion analyses exhibit reduced sensitivity for identifying inducible ischemia in elderly.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal medicine, Section on Cardiology, Wake Forest School of Medicine, Winston Salem, North Carolina, 27157, USA. svasu@wakehealth.edu.

ABSTRACT

Background: Dobutamine associated left ventricular (LV) wall motion analyses exhibit reduced sensitivity for detecting inducible ischemia in individuals with increased LV wall thickness. This study was performed to better understand the mechanism of this reduced sensitivity in the elderly who often manifest increased LV wall thickness and risk factors for coronary artery disease.

Methods: During dobutamine cardiovascular magnetic resonance (DCMR) stress testing, we assessed rate pressure product (RPP), aortic pulse wave velocity (PWV), LV myocardial oxygen demand (pressure volume area, PVA, mass, volumes, concentricity, and the presence of wall motion abnormalities (WMA) and first pass gadolinium enhanced perfusion defects (PDs) indicative of ischemia in 278 consecutively recruited individuals aged 69 ± 8 years with pre-existing or known risk factors for coronary artery disease. Each variable was assessed independently by personnel blinded to participant identifiers and analyses of other DCMR or hemodynamic variables.

Results: Participants were 80% white, 90% hypertensive, 43% diabetic and 55% men. With dobutamine, 60% of the participants who exhibited PDs had no inducible WMA. Among these participants, myocardial oxygen demand was lower than that observed in those who had both wall motion and perfusion abnormalities suggestive of ischemia (p = 0.03). Relative to those with PDs and inducible WMAs, myocardial oxygen demand remained different in these individuals with PDs without an inducible WMA after accounting for LV afterload and contractility (p = 0.02 and 0.03 respectively), but not after accounting for either LV stress related end diastolic volume index (LV preload) or resting concentricity (p = 0.31-0.71).

Conclusions: During dobutamine stress testing, elderly patients experience increased LV concentricity and declines in LV preload and myocardial oxygen demand, all of which are associated with an absence of inducible LV WMAs indicative of myocardial ischemia. These findings provide insight as to why dobutamine associated wall motion analyses exhibit reduced sensitivity for identifying inducible ischemia in elderly.

Trial registration: This study was registered with Clinicaltrials.gov (NCT00542503).

No MeSH data available.


Related in: MedlinePlus