Outcomes of an Institutional Algorithm Using Low-Dose Catheter-Directed Thrombolysis for the Treatment of Submassive Pulmonary Embolism
Gautam Anand, MD, Khalil Qato, MD, Allan M. Conway, MD, Laurie Mondry, BSN, Bushra Mina, MD, Gary Giangola, MD, Alfio Carroccio, MD.
Northwell Health - Lenox Hill Hospital, New York, NY, USA.
Objective: Management of submassive pulmonary embolism (SMPE) with catheter directed thrombolysis (CDT) has gained favor due to the lower incidence of major bleeding compared to systemic thrombolysis. Our study aims to assess the short-term outcomes of an institutional algorithm for the management of SMPE using low-dose catheter-directed thrombolysis.
Methods: Patients with SMPE from October 2015 to September 2017 were entered into a prospectively maintained database. Once a diagnosis of SMPE was made, patients were offered low-dose thrombolytic infusion if symptoms or abnormal hemodynamics did not resolve within 24-48 hours. Right and left pulmonary artery catheters were advanced from bilateral common femoral venous access. A bolus of alteplase was delivered, followed by infusion of alteplase at 1 mg/hour for four hours then 0.5 mg/hour. The catheters were removed at bedside with no return to the angiography suite once symptoms resolved and/or pulmonary pressures normalized (< 25 mmHg). We assessed our data for indication, pre- and post-intervention PAP, resolution of symptoms, and complication rate.
Results: A total of 115 patients were diagnosed with a SMPE. Twenty-eight patients were treated as per our algorithm; the remainder was excluded for resolution of symptoms or rapid deterioration. Twelve (42.9%) were male, and mean age was 59.7 ± 16.8 years. Thirteen (46.4%) had elevated troponin, 28 (71.4%) had elevated proBNP, 26 (92.9%) had right heart strain detected by echocardiography, and 21 (75%) had right heart strain seen on computed tomography. Table 1 lists the results.
Table 1
| Variable | Mean ± Standard Deviation |
| Heart rate (beats per minute) | 105.1 ± 14.5 |
| Serum troponin (ng/dL) | 0.69 ± 0.64 |
| Serum proBNP (pg/mL) | 5804.9 ± 4728.7 |
| Pre-lysis PAP by pulmonary catheter (mm Hg) | 38.9 ± 19.1 |
| Pre-lysis PAP by echocardiography (mm Hg) | 56.6 ± 12.4 |
| Post-lysis PAP by pulmonary catheter (mm Hg) | 20.1 ± 6.4 |
| Post-lysis PAP by echocardiography (mm Hg) | 42.2 ± 10.2 |
| PAP decrease by pulmonary catheter (%) | 45.7 ± 20.1 |
| Intra-operative alteplase bolus (mg) | 5.7 ± 3.9 |
| Total alteplase dose administered (mg) | 23.8 ± 9.0 |
| Duration of thrombolysis (hours) | 16.5 ± 5.9 |
| Length of stay (days) | 5.1 ± 2.3 |
Mean decrease in PAP was 45.7% based on direct pulmonary artery catheter measurement. Unpaired t-test showed a statistically significant decrease in pre- versus post-lysis PAP (p<0.0001, 95% CI [11.16, 26.43]). All patients had resolution of SMPE (given absence of symptoms and normalization of PAP) by 16.5 hours on average. There were no deaths, nor any episodes of major bleeding.
Conclusions: We have demonstrated the effectiveness and safety of an institutional algorithm for the management of SMPE, which uses low doses of thrombolytic agent without the need for return to the angiography suite. Long-term follow up is needed to determine if this strategy is effective in preventing chronic pulmonary hypertension.
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