Examination of the validity of the DPTI as an estimate of myocardial oxygen supply with special reference to the DPTI/TTI ratio

Baller, D.; Jonas, Wenke; Sigmund-Duchanova, H.; Prennschütz-Schützenau, H.; Zipfel, J.; Hellige, G.

doi:10.1007/bf01906797

Cited by 12 publications

(13 citation statements)

References 10 publications

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“…The hemodynamic recordings were analyzed at baseline and support conditions to obtain indices of LV function and peripheral perfusion. The diastolic pressure time index (DPTI), the area between the aortic pressure signal and LV pressure signal in diastole, was calculated as a measure for diastolic coronary perfusion (15,16). The tension time index (TTI), the enclosed area under the systolic LV pressure curve, was calculated as a measure for LV afterload (15,17,18).…”

Section: Methodsmentioning

confidence: 99%

The Acute Effect of Intra‐aortic Balloon Counterpulsation During Extracorporeal Life Support: An Experimental Study

et al. 2006

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Hemodynamically unstable patients supported by an extracorporeal life support (ECLS) circuit often receive additional support by intra-aortic balloon pump (IABP). However, it is not established whether support of the failing heart is improved by adjunctive IABP in both peripheral cannulation (PC) and central cannulation (CC) settings. Seven sheep were supported by an IABP and an ECLS system which were cannulated centrally as well as peripherally. In each cannulation configuration, hemodynamic and cardiac function indices were measured at baseline, ECLS, and ECLS plus IABP. The primary variables were mean coronary artery flow (Qcor), diastolic pressure time index (DPTI), left ventricular (LV) pressure-volume area (PVA), and tension time index (TTI). Additional IABP with ECLS support (CC/PC) decreased LV afterload (LV systolic peak pressure -4%, P<0.05/-8%, P<0.02), as well as TTI -2%/-10% and PVA -10%/-12% (P<0.03). Coronary perfusion was increased by additional IABP: CC, Qcor, +9%, and DPTI, +18% (P<0.02); PC, Qcor,+6%, and DPTI, +11% (P<0.05). IABP augmented the myocardial oxygen supply/demand ratios (CC/PC): Qcor/(PVA.heart rate) (+21%/+22%, P<0.02) and DPTI/TTI (+27%/+24%, P<0.03). In case of low arterial pressure (<50 mm Hg) and reduced ECLS flow, the overall hemodynamic profile improved only with central cannulation. We conclude that in both central and peripheral ECLS cannulation settings, adjunctive IABP improves the myocardial oxygen supply demand balance. In case of low cardiac output and insufficient extracorporeal flow with PC, adjunctive IABP may be contraindicated.

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Section: Methodsmentioning

confidence: 99%

The Acute Effect of Intra‐aortic Balloon Counterpulsation During Extracorporeal Life Support: An Experimental Study

et al. 2006

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“…The tension-time index is better called systolic pressure-time index (13), since it does not evaluate systolic wall tension due to neglect of ventricular dimensions. In the last years "TTI" won further importance as a predictor of MVO2 in connection with a diastolic pressure-time index (DPTD as a predictor of myocardial oxygen supply forming together the myocardial supply/demand ratio (DPTI/TTI) (23,24), which has been critically examined in recent works (25,26).…”

Section: Valuation Of Indirect Oxygen Demand Indicesmentioning

confidence: 99%

A critical look at currently used indirect indices of myocardial oxygen consumption

1981

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SummaryMyocardial oxygen consumption indices that are frequently applied to man such as tension-time index (TTI), pressure-rate product (P 9 HR) and triple product (TP) have not been fully validated so far. These easily obtainable indices and a modified TTI (P -x/H--R), therefore, were examined in I0 closed-chest dogs with very broad variations of hernodynarnics and oxygen consumption (3-36 rnl/rnin -100 g) analyzing 162 steady states. Myocardial blood flow was directly measured by a differential pressure coronary sinus catheter. I~O 2 was varied by administration of catecholamines and other inotropic drugs, atropine, beta-blocking agents and hypoand hypervolernia. Over a wide range of hernodynarnic states, correlations with directly measured MVO 2 of TTI (r = 0.63), P 9 HR (r = 0.87), TP (r = 0.65) and P 9 %/HR (r = 0.80) are not satisfactory due to neglect of contractility and cardiac volumes by these terms. Better correlations are obtained when relating these indices to IV[Vo2 under different inotropic states. At normal and moderately increased contractility, correlations with M~O2 rose as follows: TTI (r = 0.96), P 9 HR (r = 0.91), TP (r = 0.96) and P 9 ~ (r = 0.94). Significant rises in correlation are due to the close relationship between peak pressure and dP/dtma x at only moderately increased contraction velocity. Correlation differences within this inotropic range must be related to incorporation or neglect of ejection time as a partial determinant of MVO 2. At markedly increased contractility, results for these indices, however, are in part very poor: TTI (r = 0.40), P -HR (r = 0.81), TP (r = 0.38) and P 9 ~/HR (r = 0.76). Within this inotropic state neglect of dP/dtma x as a rna]or determinant of MVO 2 and the inverse relationship between ejection time and dP/dtma x mainly account for these correlation shifts. It is concluded that non-invasively obtainable indices, currently in use, are no reliable predictors of actual overall MVO2 of the left ventricle if the contractile state of the rnyocardium is not checked invasively before. The broad variability of the relation of the energy demand of velocity of tension development to rnaintenance of systolic wall tension is not sufficiently considered by these terms. Appropriate caution, therefore, is necessary when applying those indirect indices of M'~rO2 to humans.

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“…We have shown recently that the DPTI is not a useful indicator for predicting myocardial oxygen supply under conditions of maintained metabolic regulation of coronary blood flow (5). From the results of our first report on the validity of the DPTI/ST"rI ratio we may conclude that calculation of the EVR leads to false conclusions about the myocardial 02 supply/demand ratio for all cases without hypoxia induced maximal dilation of coronary vessels.…”

Section: Discussionmentioning

confidence: 85%

“…Details of the experimental procedure and the technics of measurements have been described previously (5). We analyzed 89 steady states in intact dogs.…”

Section: Methodsmentioning

confidence: 99%

“…A digital computer has been introduced to calculate the ratio of DPTI/S2~rI and display continuously the result as the endocardial viability ratio (EVR = DPTI/S2~rI) (4). We have recently demonstrated experimentally that the ratio of DPTI/STTI does not correlate with the directly measured ratio of O2 supply/O2 demand under conditions of intact metabolic regulation of coronary blood flow over a wide range of testing (5). We have recently demonstrated experimentally that the ratio of DPTI/STTI does not correlate with the directly measured ratio of O2 supply/O2 demand under conditions of intact metabolic regulation of coronary blood flow over a wide range of testing (5).…”

Section: Sul'nmarymentioning

confidence: 95%

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Prediction of myocardial blood flow by DPTI and prediction of the adequacy of myocardial O2 supply by the DPTI/STTI ratio under maximal coronary dilation

et al. 1979

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The DPTI/STTI ratio as an estimate of the myocardial 02 supply/demand ratio and the prediction of myocardial blood flow (MBF) by the diastolic pressure time index (DPTD and other indices have been examined in intact anesthetized dogs. We analyzed 89 steady states including maximal alterations of the variables determining DPTI and STI~I. Myocardial blood flow was directly measured in the coronary sinus with a differential pressure catheter. An experiments were carried out under maximal coronary dilation obtained by application of dipyridamol. Hemodynamics and MBF were varied by use of pressure loading, (3-stimulation and ~-blockade, hypo-and hypervolemia, electrical stimulation and hemodilution. Hemodynamic variations included clinically significant situations such as tachycardiac heart failure based on exhausted coronary vascular reserve and severe anemia. Parameters of sufficient myocardial 02 supply were coronary venous 02 saturation, precordial Ecg, hemodynamic evaluation of myocardial performance, result of autopsy and determination of the wet and dry weight ratio.All tested parameters show a poor correlation for prediction of MBF. Correlation coefficient for DPTI is r = 0.60. Using the primary data of Buckberg(1) we obtained similar results for the correlation of DPTI to subendocardial blood flow measured with microspheres (r = 0.65). The highest r (0.66) was found in our data for the difference between mean diastolic aortic pressure and mean left ventricular diastolic pressure without regard to diastolic duration. Therefore, in contrast to theoretical expectation, diastolic duration is not a practically important determinant of MBF. A number of DPTI/STrI ratios fell far below the critical values *) Supported by the Deutsche Forschungsgemeinschaft, SFB 89, Kardiologie, GSttingen. 811

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Examination of the validity of the DPTI as an estimate of myocardial oxygen supply with special reference to the DPTI/TTI ratio

Cited by 12 publications

References 10 publications

The Acute Effect of Intra‐aortic Balloon Counterpulsation During Extracorporeal Life Support: An Experimental Study

The Acute Effect of Intra‐aortic Balloon Counterpulsation During Extracorporeal Life Support: An Experimental Study

A critical look at currently used indirect indices of myocardial oxygen consumption

Prediction of myocardial blood flow by DPTI and prediction of the adequacy of myocardial O2 supply by the DPTI/STTI ratio under maximal coronary dilation

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