**3.4.5 Clinical experience**

Between December 2009 and May 2011, a total of 49 patients underwent removal of undesirable intravascular material using the funnel-tipped venous drainage cannula under extracorporeal veno-venous bypass. Procedures were conducted both in the fluoroscopy suite, and in the surgical theater under C-arm guidance. Veno-occlusive states addressed by these procedures included the following: (1) A retained segment of fibrin sheath from a pacemaker lead was extracted from the right atrium of a patient. (2) Vegetation was removed from the tricuspid valve of a patient who developed endocarditis from an indwelling line. (3) Thrombus and tumor was removed from a patient with an inferior vena cava occlusion due to a retroperitoneal malignancy. (4) A saddle embolus was removed from a patient with pulmonary embolism. (5) Organized and soft thrombus was removed from a patient presenting with bilateral iliofemoral and inferior vena cava occlusion. IVC thrombosis and pulmonary embolism accounted for the majority of the procedures, 43% and 29%, respectively. Seven patients had right atrial thrombus removed via suction embolectomy; in four of these patients, the thrombus extended up into the superior vena cava, and cannulation of the the SVC was required to remove the occluding clot. Four patients had vegetative endocarditic masses removed from their right atria. Several representative procedures may be detailed as follows:

### Example 1:

Saline Bath with Heater and Circulator

Pump Pulsatile

ID 1/2"

Pump

Funnel Cannula Circuit with Filter A 63 year old female presented with severe bilateral lower extremity edema, bordering on phlegmasia cerulean dolens. She had an inferior vena cava filter placed two weeks previously for deep venous thrombosis, and her history is also significant for a recent neurosurgical procedure. The patient's situation was additionally complicated by a documented history of heparin induced thrombocytopenia. A venogram demonstrated complete IVC thrombosis extending proximal to the IVC filter and involving both iliofemoral systems distally (Figure 4).

Thrombolytic therapy was contraindicated in this patient, due to the recent neurosurgical procedure and the history of heparin induced cytopenia. Rheolytic thrombectomy, applied in an attempt to recanalize the vena cava and distal venous circulation, was unsuccessful. The patient was brought back to the fluoroscopy suite, where the suction funnel cannula was inserted through a 26F introducer sheath via a percutaneous right femoral vein entry site. Upon establishment of flow via the centrifugal pump, a large amount of fresh and organized thrombus was retrieved in the filter. The suction cannula was advanced into the vena cava, as well as the contralateral iliac vein. Two full filter canisters of occluding material, totaling 180 cc in volume, was removed from the patient (Figure 5). In addition, the

Application of a Novel Venous Cannula for

Fig. 5. Thrombotic material captured in two filters

discharged from the hospital under anticoagulation.

En-Bloc Removal of Undesirable Intravascular Material 137

Fig. 6. Completion venogram demonstrating recanalization of the IVC and iliac veins

mobile thrombus, and a patent proximal superior vena cava (Figure 9). The sessile mass remained attached to the wall of the right atrium; no additional attempts were made to detach this immobile mass. A new dialysis catheter was placed, and the patient was

### Fig. 4. Venogram depicting complete IVC thrombosis

previously placed IVC filter was removed through the central lumen of the suction cannula, while the extracorporeal circulation was maintained to prevent distal embolization from occurring during vena caval filter retrieval. Upon completion of the embolectomy procedure, a new IVC filter was placed. The post-extraction venogram showed a widely patent IVC and iliofemoral vasculature (Figure 6). The patient remained stable throughout the procedure. The procedure was conducted under administration of intravenous Bivalirudin (Angiomax®, The Medicines Company, Parsippany, NJ), due to the patient history of heparin induced thrombocytopenia.

### Example 2:

A 40kg 23 year old female on renal dialysis via an indwelling right subclavian catheter, with a history of end stage renal disease and a failed renal transplant, presented with chest pain. She was found to have an embolus in a distal lobar branch of the left pulmonary artery, and an echocardiogram and CT scan revealed a fluttering clot at the distal tip of the subclavian catheter, and a 3 cm sessile mass on the free wall of the right atrium (Figure 7). Suction embolectomy was performed under general anesthesia in the operating room under echocardiographic guidance. Due to the small stature of the patient and subsequent limited caliber of her vasculature, the left and right femoral veins were exposed via open groin incisions. The 22F funnel cannula was introduced directly into the right femoral venotomy, and a 17F cannula placed into the left femoral vein for reinfusion. The funnel cannula was advanced into the right atrium and positioned in proximity to the subclavian catheter. Flow was initiated with the centrifugal pump, and chronic thrombotic material trapped by the filter. The subclavian dialysis catheter was removed, and the cannula advanced into the superior vena cava while circulating flow was maintained. A large amount of organized thrombus was noted in the filter (Figure 8). The echocardiogram showed removal of all

previously placed IVC filter was removed through the central lumen of the suction cannula, while the extracorporeal circulation was maintained to prevent distal embolization from occurring during vena caval filter retrieval. Upon completion of the embolectomy procedure, a new IVC filter was placed. The post-extraction venogram showed a widely patent IVC and iliofemoral vasculature (Figure 6). The patient remained stable throughout the procedure. The procedure was conducted under administration of intravenous Bivalirudin (Angiomax®, The Medicines Company, Parsippany, NJ), due to the patient

A 40kg 23 year old female on renal dialysis via an indwelling right subclavian catheter, with a history of end stage renal disease and a failed renal transplant, presented with chest pain. She was found to have an embolus in a distal lobar branch of the left pulmonary artery, and an echocardiogram and CT scan revealed a fluttering clot at the distal tip of the subclavian catheter, and a 3 cm sessile mass on the free wall of the right atrium (Figure 7). Suction embolectomy was performed under general anesthesia in the operating room under echocardiographic guidance. Due to the small stature of the patient and subsequent limited caliber of her vasculature, the left and right femoral veins were exposed via open groin incisions. The 22F funnel cannula was introduced directly into the right femoral venotomy, and a 17F cannula placed into the left femoral vein for reinfusion. The funnel cannula was advanced into the right atrium and positioned in proximity to the subclavian catheter. Flow was initiated with the centrifugal pump, and chronic thrombotic material trapped by the filter. The subclavian dialysis catheter was removed, and the cannula advanced into the superior vena cava while circulating flow was maintained. A large amount of organized thrombus was noted in the filter (Figure 8). The echocardiogram showed removal of all

Fig. 4. Venogram depicting complete IVC thrombosis

history of heparin induced thrombocytopenia.

Example 2:

Fig. 5. Thrombotic material captured in two filters

Fig. 6. Completion venogram demonstrating recanalization of the IVC and iliac veins

mobile thrombus, and a patent proximal superior vena cava (Figure 9). The sessile mass remained attached to the wall of the right atrium; no additional attempts were made to detach this immobile mass. A new dialysis catheter was placed, and the patient was discharged from the hospital under anticoagulation.

Application of a Novel Venous Cannula for

**3.4.6 Clinical results** 

remained stable post procedure.

En-Bloc Removal of Undesirable Intravascular Material 139

Fig. 9. Post extraction echocardiogram depicting absence of mobile thrombus

Of the 49 total patients in this series, 27 patients were male, and 22 female. The average age of the male patients was 53 years with a range between 27 and 88 years, and the average age of the female patients was 51 years, with a range between 19 and 82 years. Twelve of the procedures were performed in a totally percutaneous manner, while thirty-seven procedures were performed via surgical exposure of the femoral veins. Success of an extraction procedure is defined as removal of occluding material, fluoroscopic or echocardiographic evidence of venous patency, and stabilization of patient hemodynamic parameters. Forty of the forty-nine procedures resulted in removal of intravascular material for an 80% overall success rate. In 9 cases, minimal or no material was removed. In one case, spontaneous fragmentation and distal embolization of the thrombus occurred prior to initiation of the suction embolectomy procedure. One perioperative death occurred in a hemodialysis patient with a right atrial mass and an inferior vena cava occlusion. Hemothorax from a suspected guidewire perforation of the right atrium was noted during the procedure. The patient was brought to the operating room, and surgical exploration found a substantial fibrotic mass encasing the right atrium and inferior vena cava, preventing cannulation for cardiopulmonary bypass. The patient survived the surgery, but succumbed within 48 hours in the intensive care unit. No hemolysis or thrombocytopenia was observed in any of the patients in this study, and the patients' hematocrit values

Fig. 7. Echocardiogram depicting mobile thrombus and sessile mass in the right atrium

Fig. 8. Organized thrombus extracted from right atrium and superior vena cava

Fig. 7. Echocardiogram depicting mobile thrombus and sessile mass in the right atrium

Fig. 8. Organized thrombus extracted from right atrium and superior vena cava

Fig. 9. Post extraction echocardiogram depicting absence of mobile thrombus
