Intravascular ultrasound-guided pulmonary artery embolectomy for saddle pulmonary embolism

Role of Intravascular Ultrasound in Pulmonary Embolism Patients Undergoing Mechanical Thrombectomy: A Systematic Review

BACKGROUND

Traditionally, mechanical thrombectomy performed for pulmonary embolism (PE) necessitates the utilization of iodinated contrast. Intravascular ultrasound (IVUS) has been used as a diagnostic and therapeutic modality in the management of acute high and intermediate-risk PE. Recently, with the shortage of contrast supplies and the considerable incidence of contrast-induced acute kidney injury (CI-AKI), other safer and more feasible IVUS methods have become desirable. The purpose of this systematic review was to evaluate the importance of IVUS in patients with PE undergoing thrombectomy.

METHODS

Medline/PubMed, Embase, Scopus, and Google Scholar were searched for review studies, case reports, and case series. Clinical characteristics, outcomes and the usage of IVUS-guided mechanical thrombectomy during the treatment of acute high and intermediate-risk PE were examined in a descriptive analysis.

RESULTS

In this systematic review, we included one prospective study, two case series, and two case reports from July 2019 to May 2023. A total of 39 patients were evaluated; most were female (53.8%). The main presenting symptoms were dyspnea and chest pain (79.5%); three patients (7.9%) presented with syncope, one with shock and one with cardiac arrest. Biomarkers (troponin and BNP) were elevated in 94.6% of patients. Most patients (87.2%) had intermediate-risk PE, and 12.8% had high-risk PE. All patients presented with right-heart strain (RV/LV ratio ≥ 0.9, n = 39). Most patients (56.4%) had bilateral PE. Mechanical thrombectomy was performed using IVUS without contrast utilization in 39.4% of the patients. After the initial learning curve, contrast usage decreased gradually over time. There was a significant decrease in the composite mean arterial pressure immediately following IVUS-guided thrombectomy from 35.1 ± 7.2 to 25.2 ± 8.3 mmHg (p < 0.001). Post-procedure, there was no reported (0%) CI-AKI, no all-cause mortality, no major bleeding, or other adverse events. There was a significant improvement in symptoms and RV function at the mean follow-up.

CONCLUSIONS

New evidence suggests that IVUS-guided mechanical thrombectomy is safe, with visualization of the thrombus for optimal intervention, and reduces contrast exposure.

Intravascular ultrasound guidance in percutaneous mechanical thrombectomy: A single-center experience from the FLASH registry

BACKGROUND

Traditionally, iodinated contrast is utilized during catheter-based mechanical thrombectomy for pulmonary embolism (PE). Recently, there have been disruptive contrast shortages. Furthermore, contrast can cause contrast-induced acute kidney injury especially in patients with pre-existing chronic kidney disease, necessitating an alternative imaging method. We present utilization and feasibility of an intravascular ultrasound (IVUS)-guided strategy for mechanical thrombectomy in PE from the FLASH registry.

METHODS

In this FLASH patient subset, IVUS was used to image the pulmonary arteries (PAs) before and after mechanical thrombectomy with the FlowTriever System at one study site comprising three hospitals. The Philips Visions PV 0.035" IVUS catheter was used for all the IVUS-guided cases in a standardized manner.

RESULTS

Between July 2019 and December 2021, 26 FLASH patients enrolled at this site underwent IVUS-guided thrombectomy. Most patients (96.2 %) had intermediate-risk PE and 3.8 % had high-risk PE. The mean baseline composite RV/LV ratio was 1.36 ± 0.27 and the mean simplified Pulmonary Embolism Severity Index (sPESI) score was 1.9 ± 1.2. A decreasing trend in contrast agent volume usage was observed over time and several later procedures were performed with IVUS guidance alone. Mean PA pressure significantly decreased immediately following thrombectomy from 34.8 ± 8.3 to 25.5 ± 7.3 mmHg (p < 0.0001). Systolic PA pressure also significantly decreased immediately from 55.4 ± 13.9 to 39.5 ± 12.5 mmHg (p < 0.0001). Significant improvements were seen in echocardiographic assessments of RV function at a mean 87-day follow-up compared with baseline.

CONCLUSIONS

In conclusion, the use of IVUS guidance with minimal or no angiographic contrast during mechanical thrombectomy for acute PE is technically feasible.

Intravascular ultrasound-guided catheter-based aspiration thrombectomy in patients with acute submassive pulmonary embolism: A case series

Contrast pulmonary angiography by hand injection or power injection is widely used during catheter-based therapies for acute submassive and massive pulmonary embolism (PE). Particularly, in patients with pre-existing chronic kidney disease, this approach may present a prognostic challenge owing to a double-contrast load, initially during computed tomographic pulmonary angiography (CTPA), and during percutaneous treatment. Intravascular ultrasound (IVUS) has been used as an adjunctive imaging modality in the percutaneous treatment of chronic thromboembolic pulmonary hypertension, and in coronary and peripheral vascular interventions. We report a series of cases illustrating the use of IVUS in the management of acute PE. All five patients presented with an acute submassive PE with evidence of right ventricular (RV) strain (RV/LV ratio ≥ 0.90). Body mass index and B-type natriuretic peptide ranged from 18 to 47 kgm/m² and 56-932 pg/mL (ref. ≤ 78), respectively. Three of the five patients had renal impairment prior to the procedure (acute kidney injury, AKI, and chronic kidney injury, CKD). Post-catheter-directed pulmonary embolectomy there was a modest reduction in mean pulmonary artery pressure in all five patients (range: -4 mmHg to -9 mmHg). The first case serves as a proof of concept of IVUS use in acute PE. This case series demonstrates that an IVUS-only approach in the catheter-directed management of acute submassive PE is feasible and may be of particular importance in patients with pre-existing renal dysfunction.