Effects of Heart Rate and Pulmonary Artery Pressure on Doppler Pulmonary Artery Acceleration Time in Experimental Acute Pulmonary Hypertension

doi:10.1378/chest.100.2.470

Chest

Volume 100, Issue 2, August 1991, Pages 470-473

https://doi.org/10.1378/chest.100.2.470 Get rights and content

Chronic pulmonary hypertension in humans is characterized by shortening of the pulmonary artery acceleration time as measured by Doppler echocardiography, such that the higher the pulmonary artery pressure, the shorter the pulmonary acceleration time. Increases in heart rate are also known to produce decreases in the pulmonary artery acceleration time. To explore the relationship between mean pulmonary artery pressure, heart rate, and Doppler pulmonary artery acceleration time, experimental acute pulmonary hypertension was created in nine Duroc swine, either by infusion of Sephadex beads with embolization of the pulmonary arterial circulation or by partially occluding the main pulmonary artery 8 to 10 cm distal to the pulmonic valve. Pulmonary artery Doppler flow velocity recordings and invasive pressure measurements were made at baseline and at paced atrial rates ranging from 60 to 160 beats per minute, in 20-beat increments. The results in this acute animal model reveal that increases in heart rate produced significant decreases in Doppler pulmonary artery acceleration time at mean pressures below 25 mm Hg. However, with mean pulmonary artery pressures greater than 25 mm Hg, both heart rate and increases in pulmonary artery pressure had no significant effect on acceleration time.

(Chest 1991; 100:470-73)

Section snippets

METHODS

Nine Duroc 50- to 90-kg swine were anesthetized with intramuscular ketamine (25 mg/kg), endotracheally intubated, and maintained anesthetized on a ventilator using 0.5 to 2.0 percent halothane. Surgical cutdowns were performed on the right and left carotid arteries and veins. A 7.5-French (Fr) Could balloon-tipped flow-directed pulmonary artery thermodilution catheter was advanced under fluoroscopic guidance into the right pulmonary artery. An arterial pressure line was established in the right

RESULTS

The mean pulmonary pressure for anesthetized swine in sinus rhythm was 14 ± 4 mm Hg (see Table 1). The mean pulmonary artery pressure was easily varied by either bead injection or pulmonary clamping up to 45 mm Hg. Incremental injections of beads were performed at 30-minute intervals. This interval was chosen as it took about 30 minutes for the collection of data for all heart rates from 50 to 160 beats per minute at each pulmonary artery pressure. Attempts to raise mean pulmonary artery

DISCUSSION

We have developed a model of acute pulmonary hypertension in swine. Bead-induced pulmonary hypertension does not appear to be reversible. Pulmonary clamping produces reproducible elevations in mean pulmonary artery pressure, with the potential benefit of reversibility of the induced obstruction to pulmonary artery blood flow. Pulmonary artery pressure may be returned toward normal if unacceptable systemic hypotension occurs by removing the clamp. An additional characteristic of the pulmonary

ACKNOWLEDGMENT

The authors would like to acknowledge the superb technical assistance of Alice Allfie, the statistical assistance of Nathan Wong, Ph.D., and the laboratory space provided by Orhan Nalcioglu, Ph.D.

REFERENCES (6)

DabestaniA et al.
Evaluation of pulmonary artery pressure and resistance by pulsed Doppler echocardiography.
Am J Cardiol
(1987)
GardinJM et al.
Effect of acute changes in heart rate on Doppler pulmonary artery acceleration time in a porcine model.
Chest
(1988)
GardinJM et al.
Evaluation of blood flow velocity in the ascending aorta and main pulmonary artery of normal subjects by Doppler echocardiography.
Am Heart J
(1984)

There are more references available in the full text version of this article.

Cited by (34)

Endobronchial ultrasound: A novel screening test for pulmonary hypertension prior to major pulmonary surgery
2024, JTCVS Techniques
Pulmonary hypertension (PH) is an important physiologic variable in the assessment of patients undergoing major thoracic operations but all too often neglected because of the need for right heart catheterization (RHC) due to the inaccuracy of transthoracic echocardiography. Patients with lung cancer often require endobronchial ultrasound (EBUS) as part of the staging of the cancer. We sought to investigate whether EBUS can be used to screen these patients for PH.
Patients undergoing a major thoracic operation requiring EBUS for staging were included prospectively in the study. All patients had also a RHC (gold standard). We aimed to compare the pulmonary artery pressure measurements by EBUS with the RHC values.
A total of 20 patients were enrolled in the study. The prevalence of abnormal pulmonary artery pressure was 65% based on RHC. All patients underwent measurement of the pulmonary vascular acceleration time (PVAT) by EBUS with no adverse events. Linear regression analysis comparing PVAT and RHC showed a correlation (r = −0.059, −0.010 to −0.018, P = .007). A receiver operator characteristic curve (area under the curve = 0.736) was used to find the optimal PVAT threshold (140 milliseconds) to predict PH; this was used to calculate a positive and negative likelihood ratio following a positive diagnosis of 2.154 and 0.538, respectively.
EBUS interrogation of pulmonary artery hemodynamic is safe and feasible. EBUS may be used as a screening test for PH in high-risk individuals.
New measures of right ventricle-pulmonary artery coupling in heart failure: An all-cause mortality echocardiographic study
2021, International Journal of Cardiology
Citation Excerpt :
It is known that PH is not the only factor that affects pACT [17], as pulmonary vascular resistance and heart rate are inversely correlated with pACT [27]. However, in experimental models the effect of heart rate on pACT was shown not to be significant when mean PAP was elevated (>25 mmHg) [28]. In our study, a few patients had heart rate > 100 bpm (less then 15%) and no effect of heart rate was seen on the predictive power of TAPSE x pACT (P for interaction =0.929); in addition, no adjunctive prognostic effect was observed when correcting pACT for heart rate (Table S2).
Right ventricle-pulmonary artery coupling (RVPAC) has emerged from pathophysiology to clinical interest for prognostic implication in heart failure and is commonly measured as the ratio between tricuspid annular plane systolic excursion and systolic pulmonary artery pressure (TAPSE/SPAP). However, feasibility of SPAP is limited (down to 60% in trials, and maybe lower in clinical practice). We ought to assess the prognostic value of the TAPSE times pulmonary acceleration time (TAPSE x pACT) product and TAPSE to peak tricuspid regurgitation velocity (TAPSE/TRV) ratio as new alternative measures of RVPAC.
Two-hundred patients hospitalized with heart failure were followed-up (median time of 2.7 years) and 82 died. Non survivors had significantly lower TAPSE/SPAP, TAPSE x pACT and TAPSE/TRV than survivors (0.31 vs 0.40 mm/mmHg, 130 vs 156 cm·ms, 5.0 vs 5.8 ms, respectively). Four multivariate models were performed, each one including TAPSE, TAPSE/SPAP, TAPSE x pACT or TAPSE/TRV. TAPSE/SPAP resulted the most powerful predictor of mortality (HR 0.74 per mm/mmHg increase, P < 0.001, C-Statistic 0.778), followed by TAPSE x pACT (HR 0.95 per 10 cm·ms increase, P = 0.013, C-Statistic 0.776), TAPSE/TRV (HR 0.76 per ms increase, P < 0.001, C-Statistic 0.774) and TAPSE (HR 0.91 per mm increase, P = 0.003, C-Statistic 0.769). Cutoff values of 140 cm·ms and 5.5 ms were respectively identified for TAPSE x pACT and TAPSE/TRV with receiving operating characteristic analysis for mortality.
TAPSE x pACT product and TAPSE/TRV ratio are alternative measures of RVPAC for prognostic assessment in heart failure that can be applied if TAPSE/SPAP is not feasible.
Pulsed Doppler Echocardiography: An Historical Perspective
2018, Journal of the American Society of Echocardiography
Citation Excerpt :
These experiments revealed that increases in heart rate produced significant decreases in PA acceleration time at mean pressures < 25 mm Hg. However, with mean PA pressures > 25 mm Hg, both heart rate and increases in PA pressure had no significant effect on acceleration times.25 The description of normal pulsed Doppler flow velocities across the four cardiac valves made possible advances in quantitating intracardiac shunts and valvular regurgitant volumes.
Over the past six decades, echocardiography has evolved into an important technique for not only imaging cardiac structures, but also, by employing the Doppler equation, for assessing cardiac blood flow and tissue velocities. This review focuses on pulsed Doppler echocardiography: its principles, early development, and clinical applications. Important clinical applications include: (1) measurement of flow velocities, stroke volumes, and regurgitant and shunt volumes; (2) assessment of time intervals, e.g., pulmonary artery acceleration time as a measure of pulmonary artery pressure and resistance or the timing of mitral regurgitation in hypertrophic cardiomyopathy; (3) detection of turbulent flow in regurgitation, stenoses, and shunts, enhanced by the implementation of color Doppler; and (4) evaluation of left ventricular diastolic function in conjunction with pulsed tissue Doppler and deformation (strain) measurements.
Pulmonary Hypertension and Pulmonary Artery Acceleration Time: A Systematic Review and Meta-Analysis
2018, Journal of the American Society of Echocardiography
Citation Excerpt :
In adults, PAAT correlates inversely with heart rate in healthy control subjects, and many studies have corrected PAAT for RV ejection time, RR interval, or the square root of the RR interval. Nevertheless, at any given heart rate, PAAT shortened as PAP increased up to a mean of >25 mm Hg.35 RV systolic function and RV preload should affect PAAT, but only three studies reported RV function by tricuspid annular plane systolic excursion or RV fraction area change in the trials that we collected.
Measuring mean pulmonary artery pressure by right-heart catheterization is the gold standard for pulmonary hypertension (PH) diagnosis. However, its invasiveness and complication leads to its limited use. The aim of this study was to determine whether echocardiography-derived pulmonary artery acceleration time (PAAT) possesses adequate diagnostic performance for PH, using right-heart catheterization as a reference standard.
MEDLINE, Embase, PubMed, and the Cochrane Central Register of Controlled Trials were searched through July 2016 for studies evaluating PAAT for the diagnosis of PH. Methodologic quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool. For each study, the sensitivity, specificity, and diagnostic odds ratio, along with 95% CIs, were calculated to determine the diagnostic accuracy of PAAT. Meta-regression was conducted to evaluate the impact of potential confounding factors.
Of 430 articles, 21 studies (1,280 patients) were identified, including three studies that used transesophageal echocardiography and 18 studies that used transthoracic echocardiography. The pooled sensitivity across studies was 0.84 (95% CI, 0.75–0.90), the pooled specificity was 0.84 (95% CI, 0.78–0.89), and the pooled diagnostic odds ratio was 28 (95% CI, 16–49). The arrhythmia ratio in the population did not affect the specificity of PAAT's diagnostic performance and increased the sensitivity of PH detection.
The results of this study suggest that PAAT is useful for PH detection.
Assessment of pulmonary artery pressure by echocardiography-A comprehensive review
2016, IJC Heart and Vasculature
Citation Excerpt :
Heart rates outside of the normal range (< 60 or > 100 bpm) may reduce the accuracy of this technique. However, when the mean PAP exceeds 25 mmHg, RVOT acceleration time is accurate even in tachycardia [19,20]. More often, the slope of the pulse wave Doppler trace is measured, rather than the time taken from onset to peak velocity.
Pulmonary hypertension is a pathological haemodynamic condition defined as an increase in mean pulmonary arterial pressure ≥ 25 mmHg at rest, assessed using gold standard investigation by right heart catheterisation. Pulmonary hypertension could be a complication of cardiac or pulmonary disease, or a primary disorder of small pulmonary arteries. Elevated pulmonary pressure (PAP) is associated with increased mortality, irrespective of the aetiology. The gold standard for diagnosis is invasive right heart catheterisation, but this has its own inherent risks. In the past 30 years, immense technological improvements in echocardiography have increased its sensitivity for quantifying pulmonary artery pressure (PAP) and it is now recognised as a safe and readily available alternative to right heart catheterisation. In the future, scores combining various echo techniques can approach the gold standard in terms of sensitivity and accuracy, thereby reducing the need for repeated invasive assessments in these patients.
Echocardiography: Interest and border for screening and monitoring of pulmonary arterial hypertension
2011, Presse Medicale

View all citing articles on Scopus

View full text

Chest

Laboratory and Animal InvestigationsEffects of Heart Rate and Pulmonary Artery Pressure on Doppler Pulmonary Artery Acceleration Time in Experimental Acute Pulmonary Hypertension

Section snippets

METHODS

RESULTS

DISCUSSION

ACKNOWLEDGMENT

Am J Cardiol

Chest

Am Heart J

Laboratory and Animal Investigations
Effects of Heart Rate and Pulmonary Artery Pressure on Doppler Pulmonary Artery Acceleration Time in Experimental Acute Pulmonary Hypertension