Acute pulmonary thromboembolism treated successfully by balloon angioplasty--a case report

Balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension: State of the art

Chronic thromboembolic pulmonary hypertension (CTEPH) is a complex chronic disease in which pulmonary artery stenosis or obstruction caused by organized thrombus can lead to increased pulmonary artery pressure and pulmonary vascular resistance, ultimately triggering progressive right heart failure and death. Currently, its exact mechanism is not fully understood. Pulmonary endarterectomy (PEA) has immediate effects with low perioperative mortality and satisfactory prognosis in experienced expert centers for CTEPH patients with proximal lesions. Nevertheless, 37% of patients are deemed unsuitable for PEA surgery due to comorbidities and other factors, and nearly half of the operated patients have residual or recurrent pulmonary hypertension. Riociguat is the only approved drug for CTEPH, although its effect is limited. Balloon pulmonary angioplasty (BPA) is a promising alternative treatment for patients with CTEPH. After more than 30 years of development and refinements, emerging evidence has confirmed its role in patients with inoperable CTEPH or residual/recurrent pulmonary hypertension, with acceptable complications and comparable long-term prognosis to PEA. This review summarizes the pathophysiology of CTEPH, BPA history and development, therapeutic principles, indications and contraindications, interventional procedures, imaging modalities, efficacy and prognosis, complications and management, bridging and hybrid therapies, ongoing clinical trials and future prospects.

Treatment of pulmonary embolism: anticoagulation, thrombolytic therapy, and complications of therapy

During the last two decades, considerable progress in technology and clinical research methods have led to advances in the approach to the diagnosis, prevention, and treatment of acute venous thromboembolism (VTE). Despite this, however, the diagnosis is often delayed and preventive methods are often ignored. Thus, the morbidity and mortality associated with VTE remain high. The therapeutic approach to acute VTE is discussed in this article, with a particular focus on the intensive care unit setting.

Management of massive and submassive pulmonary embolism, iliofemoral deep vein thrombosis, and chronic thromboembolic pulmonary hypertension: a scientific statement from the American Heart Association

Venous thromboembolism (VTE) is responsible for the hospitalization of >250 000 Americans annually and represents a significant risk for morbidity and mortality. Despite the publication of evidence-based clinical practice guidelines to aid in the management of VTE in its acute and chronic forms, the clinician is frequently confronted with manifestations of VTE for which data are sparse and optimal management is unclear. In particular, the optimal use of advanced therapies for acute VTE, including thrombolysis and catheter-based therapies, remains uncertain. This report addresses the management of massive and submassive pulmonary embolism (PE), iliofemoral deep vein thrombosis (IFDVT),and chronic thromboembolic pulmonary hypertension (CTEPH). The goal is to provide practical advice to enable the busy clinician to optimize the management of patients with these severe manifestations of VTE. Although this document makes recommendations for management, optimal medical decisions must incorporate other factors, including patient wishes, quality of life, and life expectancy based on age and comorbidities. The appropriateness of these recommendations for a specific patient may vary depending on these factors and will be best judged by the bedside clinician.

Interventional therapies for venous thromboembolism: vena caval interruption, surgical embolectomy, and catheter-directed interventions

Therapeutic strategies other than anticoagulation sometimes require consideration in the setting of acute venous thromboembolism. Vena caval filter placement is increasingly common, in part because of the availability of nonpermanent filter devices. Filter placement, surgical embolectomy, and catheter embolectomy have not been subjected to the same prospective, randomized clinical trial scrutiny as anticoagulation but seem appropriate in certain clinical settings. The indications, contraindications, and available data supporting these therapeutic methods are discussed.

Catheter Embolectomy for Acute Pulmonary Embolism

Massive pulmonary embolism (PE) is a life-threatening condition with a high early mortality rate due to acute right ventricular failure and cardiogenic shock. As soon as the diagnosis is suspected, an IV bolus of unfractionated heparin should be administered. In addition to anticoagulation, rapid initiation of systemic thrombolysis is potentially life-saving and therefore is standard therapy. Many patients with massive PE cannot receive thrombolysis because of an increased bleeding risk, such as prior surgery, trauma, or cancer. In these patients, catheter or surgical embolectomy are helpful for rapidly reversing right ventricular failure. Catheter thrombectomy appears to be particularly useful if surgical embolectomy is not available or the patient has contraindications to surgery. Although no controlled clinical trials are available, data from cohort studies indicate that the clinical outcomes after surgical and catheter embolectomy may be comparable.

Percutaneous Catheter Thrombectomy Device for Acute Pulmonary Embolism: In Vitro and in Vivo Testing

PURPOSE

To evaluate a percutaneous pulmonary embolism (PE) thrombectomy catheter that aspirates, macerates, and removes thrombus.

MATERIALS AND METHODS

Nine in vitro tests were performed by using porcine thrombi at a PE test station that provides continuous fluid output of 2 L/min at a pressure of 50 mmHg. Macroembolization was defined as embolized particles larger than 1.5 mm in dimension; microembolization was defined as particles that range in size from 0.1 to 1.5 mm. In static in vitro tests, researchers measured plasma-free hemoglobin levels in a 36-year-old man to assess mechanical hemolysis. Investigational review board approval and informed consent were obtained. The Department of Agriculture, Veterinary Bureau, Bern, Switzerland approved in vivo tests. Researchers investigated device effectiveness in 10 pigs that developed cardiogenic shock but survived massive PE after injection of two or three porcine thrombi into the external jugular vein via a surgically implanted 24-F sheath. Pulmonary angiography and hemodynamic measurements, including mean aortic and mean pulmonary artery pressure, heart rate, and mixed venous oxygen saturation, were obtained at baseline, after embolization, and after thrombectomy. Repeated-measures analysis of variance was performed to compare hemodynamic measurements at baseline, after embolization, and after thrombectomy. Cardiovascular structures were examined at necropsy for rupture, perforation, dissection, or hemorrhage.

RESULTS

During a mean aspiration time of 69 seconds +/- 19, thrombi were completely extracted from 14-mm test tubes, with an aspirated fluid volume of 201 mL +/- 64. Although no macroembolization was observed, microembolization was quantified at 1.9 g +/- 1.3. Catheter aspiration was not associated with an increase in plasma-free hemoglobin. In 10 animals, aortic pressure increased from 52 mmHg +/- 24 before thrombectomy to 90 mmHg +/- 32 after thrombectomy, mixed venous oxygen saturation increased from 48% +/- 19% to 61% +/- 12%, pulmonary artery pressure decreased from 33 mmHg +/- 9 to 22 mmHg +/- 4, and heart rate decreased from 162 beats per minute +/- 24 to 114 beats per minute +/- 14. We did not observe macro- or microscopic damage to treated or untreated cardiovascular structures.

CONCLUSION

The PE thrombectomy device was highly effective, facilitating rapid reversal of cardiogenic shock without device-related complications.

Interventional therapy for pulmonary embolism

Venous thromboembolism is a common cause of death. Acute massive pulmonary embolism (PE) is life-threatening and may require vigorous more invasive treatment. Several risk factors are related to increased incidence of massive PE. Anticoagulation is the most traditional treatment for PE but may not suffice in cases of massive PE. Systemic thrombolytic therapy, catheter-directed thrombolysis, percutaneous embolectomy, and more recently, percutaneous thrombus fragmentation techniques with a multitude of devices are now available to treat the most severe cases of massive PE. Successful treatment of PE includes implementation of a treatment protocol and the use of associated techniques and devices.

Evaluation of a modified arrow-trerotola percutaneous thrombolytic device for treatment of acute pulmonary embolus in a canine model

PURPOSE

Massive pulmonary embolus (PE) is often rapidly fatal. Surgical thrombectomy has a mortality rate as high as 74%. Multiple percutaneous methods have been tested with limited success. The purpose of this study was to evaluate the Arrow-Trerotola percutaneous thrombolytic device (PTD) for (i) the ability to clear pulmonary embolus and (ii) the effect on normal pulmonary vasculature. These were tested in a canine model.

MATERIALS AND METHODS

Iatrogenic unilateral massive PEs were created in nine canines. These PEs were then treated with the PTD. The device was also activated in the normal pulmonary artery. Immediately after treatment, six animals were killed. Three animals were allowed to recover and underwent pulmonary arteriography 1 month later to evaluate pulmonary hypertension, stenosis, or occlusion; they were then killed. Autopsy specimens were evaluated for histologic evidence of acute or chronic vascular injury.

RESULTS

Acutely, the PTD effectively thrombolysed the PE in all animals. Histologically, there was moderate intimal injury, but no evidence of pulmonary artery disruption. There was one device failure. One month after treatment, there was no radiographic evidence of pulmonary stenosis at device activation sites, no pulmonary hypertension, and only mild histologic evidence of scar formation.

CONCLUSION

In preliminary animal testing, the PTD is safe and effective for treating large central pulmonary emboli. Human clinical trials are warranted.

A case of acute massive pulmonary thromboembolism treated by mechanical clot fragmentation using a percutaneous transluminal angioplasty balloon

Large, bilateral central pulmonary thromboemboli (PTE) led to cor pulmonale and severe hypoxemia in a patient who had undergone Hardy's operation. After several unsuccessful efforts (thrombolysis using a percutaneous catheter and aspiration of the emboli), mechanical clot fragmentation using a percutaneous transluminal angioplasty (PTA) balloon was attempted. This procedure was successful, resulting in a decrease in pulmonary artery pressure from 58/22 (mean 34) mmHg to 20/10 (mean 13) mmHg together with an increase in aortic pressure from 64/36 (mean 45) mmHg to 112/60 (mean 77) mmHg. Thus, mechanical clot fragmentation using a PTA balloon is a promising method for reducing pulmonary artery pressure and increasing aortic pressure in patients with acute PTE.

Massive pulmonary embolism: preliminary results of treatment with the Amplatz thrombectomy device

PURPOSE

To determine the feasibility of using the Amplatz thrombectomy device (ATD) to treat massive pulmonary embolism (PE).

PATIENTS AND METHODS

Five patients (four men, one woman; mean age, 45.2 years) with massive PE underwent mechanical thrombectomy with the ATD, which creates a vortex that pulverizes and recirculates the clots within the pulmonary circulation. The patients were followed up for 7-18 months after thrombectomy.

RESULTS

Marked improvement in pulmonary perfusion was observed in three patients at angiography and ventilation-perfusion scanning. No changes could be assessed in one patient who died shortly after the procedure. One patient developed hemoptysis during the procedure, most likely because of a reperfusion syndrome. A reduction in pulmonary artery pressure was observed in only one patient; the remaining patients had increased pressure. The four surviving patients were discharged within 8 days.

CONCLUSION

Mechanical thrombectomy with the ATD provides rapid debulking of thrombus in some patients with massive PE and has the potential to improve treatment and outcomes of the most sick patients.

Use of laser energy to treat central pulmonary emboli: a preliminary report

We evaluated the ability and safety of a laser fiber placed percutaneously into a pig's lobar pulmonary artery to lyse pulmonary artery blood clots that were created in situ. We developed a model to create blood clots in situ that could be placed in any desired location with a radio-opaque marker at the clot position. An excimer laser delivered energy to a flexible 600 microns fiber in three experiments and a coaxial 1.6 mm multifiber catheter in the last experiment. Pre- and postprocedure angiograms obtained from each experiment demonstrated that partial laser dissolution of central pulmonary emboli in four pigs was accomplished successfully. To avoid perforation, it is imperative that the laser fiber remain coaxial during the entire lasing process. These results suggest that laser dissolution may become an adjunctive procedure for the treatment of central pulmonary emboli in those patients who cannot be treated medically.