Relationship of clot burden and echocardiographic severity of right ventricular dysfunction after acute pulmonary embolism

Immediate cardiopulmonary responses to consecutive pulmonary embolism: a randomized, controlled, experimental study

BACKGROUND

Acute pulmonary embolism (PE) induces ventilation-perfusion mismatch and hypoxia and increases pulmonary pressure and right ventricular (RV) afterload, entailing potentially fatal RV failure within a short timeframe. Cardiopulmonary factors may respond differently to increased clot burden. We aimed to elucidate immediate cardiopulmonary responses during successive PE episodes in a porcine model.

METHODS

This was a randomized, controlled, blinded study of repeated measurements. Twelve pigs were randomly assigned to receive sham procedures or consecutive PEs every 15 min until doubling of mean pulmonary pressure. Cardiopulmonary assessments were conducted at 1, 2, 5, and 13 min after each PE using pressure-volume loops, invasive pressures, and arterial and mixed venous blood gas analyses. ANOVA and mixed-model statistical analyses were applied.

RESULTS

Pulmonary pressures increased after the initial PE administration (p < 0.0001), with a higher pulmonary pressure change compared to pressure change observed after the following PEs. Conversely, RV arterial elastance and pulmonary vascular resistance was not increased after the first PE, but after three PEs an increase was observed (p = 0.0103 and p = 0.0015, respectively). RV dilatation occurred following initial PEs, while RV ejection fraction declined after the third PE (p = 0.004). RV coupling exhibited a decreasing trend from the first PE (p = 0.095), despite increased mechanical work (p = 0.003). Ventilatory variables displayed more incremental changes with successive PEs.

CONCLUSION

In an experimental model of consecutive PE, RV afterload elevation and dysfunction manifested after the third PE, in contrast to pulmonary pressure that increased after the first PE. Ventilatory variables exhibited a more direct association with clot burden.

Right-to-left ventricular ratio is higher in systole than diastole in patients with acute pulmonary embolism

OBJECTIVES

In acute pulmonary embolism (PE), the right ventricle (RV) may dilate compromising left ventricular (LV) size, thereby increasing RV/LV ratio. End-diastolic RV/LV ratio is often used in PE risk stratification, though the cause of death is RV systolic failure. We aimed to confirm our pre-clinical observations of higher RV/LV ratio in systole compared to diastole in human patients with PE.

METHODS

We blinded and independently analyzed echocardiograms from 606 patients with PE, evaluated by a Pulmonary Embolism Response Team. We measured RV/LV ratios in end-systole and end-diastole and fractional area change (FAC). Our primary outcome was a composite of 7-day clinical deterioration, treatment escalation or death. Secondary outcomes were 7-day and 30-day all-cause mortality.

RESULTS

RV/LV ratio was higher in systole compared to diastole (median 1.010 [.812-1.256] vs. .975 [.843-1.149], p < .0001). RV/LV in systole and diastole were correlated (slope = 1.30 [95% CI 1.25-1.35], p < .0001 vs. slope = 1). RV/LV ratios in both systole and diastole were associated with the primary composite outcome but not with all-cause mortality.

CONCLUSION

The RV/LV ratio is higher when measured in systole versus in diastole in patients with acute PE. The two approaches had similar associations with clinical outcomes, that is, it appears reasonable to measure RV/LV ratio in diastole.

Clot burden of acute pulmonary thromboembolism: comparison of two deep learning algorithms, Qanadli score, and Mastora score

BACKGROUND

The deep learning convolution neural network (DL-CNN) benefits evaluating clot burden of acute pulmonary thromboembolism (APE). Our objective was to compare the performance of the deep learning convolution neural network trained by the fine-tuning [DL-CNN (ft)] and the deep learning convolution neural network trained from the scratch [DL-CNN (fs)] in the quantitative assessment of APE.

METHODS

We included the data of 680 cases for training DL-CNN by DL-CNN (ft) and DL-CNN (fs), then retrospectively included 410 patients (137 patients with APE, 203 males, mean age 60.3±11.4 years) for testing the models. The distribution and volume of clots were respectively assessed by DL-CNN(ft) and DL-CNN(fs), and sensitivity, specificity, and area under the curve (AUC) were used to evaluate their performances in detecting clots on a per-patient and clot level. Radiologists evaluated the distribution of clots, Qanadli score, and Mastora score and right ventricular metrics, and the correlation of clot volumes with right ventricular metrics were analyzed with Spearman correlation analysis.

RESULTS

On a per-patient level, the two DL-CNN models had high sensitivities and moderate specificities [DL-CNN (ft): 100% and 77.29%; DL-CNN (fs): 100% and 75.82%], and their AUCs were comparable (Z=0.30, P=0.38). On a clot level, DL-CNN (ft) and DL-CNN (fs) sensitivities and specificities in detecting central clots were 99.06% and 72.61%, and 100% and 70.63%, respectively. DL-CNN (ft) sensitivities and specificities in detecting peripheral clots were mostly higher than those of DL-CNN (fs), and their AUCs were comparable. Clot volumes measured with the two models were similar (U=85094.500, P=0.741), and significantly correlated with Qanadli scores [DL-CNN(ft) r=0.825, P<0.001, DL-CNN(fs) r=0.827, P<0.001] and Mastora scores [DL-CNN(ft) r=0.859, P<0.001, DL-CNN(fs) r=0.864, P<0.001]. Clot volumes were also correlated with right ventricular metrics. Clot burdens were increased in the low-risk, moderate-risk, and high-risk patients. Binary logistic regression revealed that only the ratio of right ventricular area/left ventricular area (RVa/LVa) was an independent predictor of in-hospital death (odds ratio 6.73; 95% CI, 2.7-18.12, P<0.001).

CONCLUSIONS

Both DL-CNN (ft) and DL-CNN (fs) have high sensitivities and moderate specificities in detecting clots associated with APE, and their performances are comparable. While clot burdens quantitatively calculated by the two DL-CNN models are correlated with right ventricular function and risk stratification, RVa/LVa is an independent prognostic factor of in-hospital death in patients with APE.

Repeat angiography in patients undergoing conventional catheter-directed thrombolysis for submassive pulmonary embolism: a large single-center experience

PURPOSE

Few studies have examined conventional catheter directed thrombolysis (CDT) for the treatment of submassive pulmonary embolism (PE). Moreover, angiographic resolution of thrombus burden following CDT has infrequently been characterized. This study describes a single-center experience treating submassive PE with CDT while utilizing repeat angiography to determine treatment efficacy.

METHODS

A retrospective analysis of 140 consecutive patients who underwent CDT for submassive PE from December 2012 to June 2019 was performed. Angiographic resolution of thrombus burden after CDT was reported as high (>75%), moderate (51-75%), low (26-50%), or insignificant (≤25%). All angiograms were reviewed by two interventional radiologists. Secondary endpoints included reduction in pulmonary artery pressure (PAP) and clinical outcomes. Bleeding events were classified according to the Society of Interventional Radiology (SIR) adverse event criteria.

RESULTS

CDT was performed in 140 patients with a mean rtPA dose of 25.3 mg and a mean treatment time of 26.0 hours. Angiographic resolution of thrombus burden was high in 70.0%, moderate in 19.3%, low in 5.7%, and insignificant in 3.6%; in 2 patients (1.4%) repeat angiography was not performed. Systolic PAP was reduced (47 vs. 35 mmHg, p < 0.001), mean PAP was reduced (25 vs 21 mmHg, p < 0.001), and 129 patients (92.1%) improved clinically. Patients with high or moderate resolution of thrombus burden had a clinical improvement rate of 95.2%, while patients with low or insignificant thrombus burden resolution had a clinical improvement rate of 76.9% (p=0.011). Ten patients (7.1%) had hemodynamic or respiratory decompensation requiring mechanical ventilation, systemic thrombolysis, cardiopulmonary resuscitation, or surgical intervention. Seven patients (5.0%) experienced moderate bleeding events and one patient (0.7%) with metastatic disease developed severe gastrointestinal bleeding that resulted in death. Thirty-day mortality was 1.4%.

CONCLUSION

In patients with submassive PE undergoing CDT, angiographic resolution of thrombus burden is a safe and directly observable metric that can be used to determine procedural success. In this study, CDT with repeat angiography was associated with a 5.7% bleeding event rate and thirty-day mortality of 1.4%.

Pulmonary artery obstruction index, pulmonary artery diameter and right ventricle strain as prognostic CT findings in patient with acute pulmonary embolism

OBJECTIVE

This study was designed to determine predictors of pulmonary hypertension and signs of right heart dysfunction caused by pulmonary embolism (PE) that may lead to early detection of high-risk patients. So the predictive value of pulmonary artery obstruction index (PAOI), measured by pulmonary CT angiography (PCTA) in the acute setting, in predicting the patients susceptible to PE cardiac complications was evaluated. Also two other PCTA indices, pulmonary artery diameter (PAD), and right ventricle (RV) strain, in these patients were investigated and their predictive value for cardiac complications on follow up echocardiography were demonstrated.

MATERIALS AND METHODS

In the study 120 patients with a definite diagnosis of PE were included. The PAOI, PAD and RV strain were measured using PCTA at the time of the initial diagnosis. Transthoracic echocardiography was done 6 months after the diagnosis of PE and RV echocardiographic indices were measured. Pearson correlation was used to investigate correlation between PAOI, PAD, RV strain and signs of right heart dysfunction.

RESULTS

PAOI was strongly correlated with systolic pulmonary artery pressure (SPAP) (r=0.83), RV systolic pressure (r=0.78) and RV wall thickness (r=0.61) in long-term follow up echocardiography. A higher rate of RV dysfunction and RV dilation was detected among the patients with higher PAOI (P<0.001). PAOI≥18 was strongly predictive for development of RV dysfunction. Also developments of pulmonary hypertension, RV systolic hypertension, RV dilation, RV dysfunction, and RV hypertrophy were significantly more common among patients with higher PAD and RV strain (P<0.001).

CONCLUSIONS

PAOI, PAD and RV strain are sensitive and specific PCTA indices that can predict the development of long-term complications such as pulmonary hypertension and right heart dysfunction, at the time of initial PE diagnosis.

Cor pulmonale: the role of traditional and advanced echocardiography in the acute and chronic settings

Cor pulmonale is the condition in which the right ventricle undergoes morphological and/or functional changes due to diseases that affect the lungs, the pulmonary circulation, or the breathing process. Depending on the speed of onset of the pathological condition and subsequent effects on the right ventricle, it is possible to distinguish the acute cor pulmonale from the chronic type of disease. Echocardiography plays a central role in the diagnostic and therapeutic work-up of these patients, because of its non-invasive nature and wide accessibility, providing its greatest usefulness in the acute setting. It also represents a valuable tool for tracking right ventricular function in patients with cor pulmonale, assessing its stability, deterioration, or improvement during follow-up. In fact, not only it provides parameters with prognostic value, but also it can be used to assess the efficacy of treatment. This review attempts to provide the current standards of an echocardiographic evaluation in both acute and chronic cor pulmonale, focusing also on the findings present in the most common pathologies causing this condition.

Triage for suspected acute Pulmonary Embolism: Think before opening Pandora's Box

This is a review of the current strengths and weaknesses of the various imaging modalities available for the diagnosis of suspected non-massive Pulmonary Embolism (PE). Without careful consideration for the clinical presentation, and the timely application of clinical decision support (CDS) methodology, the current overutilization of imaging resources for this disease will continue. For a patient with a low clinical risk profile and a negative D-dimer there is no reason to consider further workup with imaging; as the negative predictive value in this scenario is the same as imaging. While the current efficacy and effectiveness data support the continued use of Computed Tomographic angiography (CTA) as the imaging golden standard for the diagnosis of PE; this test does have the unintended consequences of radiation exposure, possible overdiagnosis and overuse. There is a persistent lack of appreciation on the part of ordering physicians for the effectiveness of the alternatives to CTA (ventilation-perfusion imaging and contrast enhanced magnetic resonance angiography) in these patients. Careful use of standardized protocols for patient triage and the application of CDS will allow for a better use of imaging resources.