The application of modular multifunctional left heart bypass circuit system integrated with ultrafiltration in thoracoabdominal aortic aneurysm repair

Abstract

Open thoracoabdominal aortic aneurysm (TAAA) repair is a complex and challenging operation with a high incidence of serious complications, and high perioperative mortality and morbidity. Left heart bypass (LHB) is a circulatory support system used to perfuse the distal aorta during TAAA operation, and the advantages of LHB include guaranteeing distal perfusion, reducing the use of heparin, and diminishing the risk of bleeding and postoperative neurological deficits. In China, the circuit for TAAA repair is deficient, and far from the perfusion requirements. We designed a modular multifunctional LHB circuit for TAAA repair. The modular circuit consisted of cannulation pipelines, functional consumables connection pipelines, and accessory pipelines. The accessory pipelines make up lines for selective visceral perfusion and kidney perfusion, suckers and rapid infusion. The circuit can be assembled according to surgical requirements. The ultrafilter and heat exchanger are integrated into the circuit to fulfill the basic demands of LHB. The LHB circuit also has pipelines for selective visceral perfusion to the celiac artery and superior mesenteric artery and renal perfusion pipelines. Meanwhile, the reserved pipelines facilitate the quick switch from LHB to conventional cardiopulmonary bypass (CPB). The reserved pipelines reduce the time of reassembling the CPB circuit. Moreover, the rapid infusion was integrated into the LHB circuit, which can rapid infusion when massive hemorrhage during the open procedures such as exposure and reconstruction of the aorta. The ultrafiltration can diminish the consequent hemodilution of hemorrhage and rapid infusion. A hemoperfusion cartridge also can be added to reduce the systemic inflammatory during operation. The circuit can meet the needs of LHB and quickly switch to conventional CPB. No oxygenator was required during LHB, which reduce the use of heparin and reduce the risk of bleeding. The heat exchanger contributes to temperature regulation; ultrafiltration, arterial filter, and rapid-infusion facilitated the blood volume management and are useful to maintain hemodynamic stability. This circuit made the assembly of the LHB circuit more easily, and more efficient, which may contribute to the TAAA repair operation performed in lower volume centers easily. 26 patients who received TAAA repair under the modular multifunctional LHB from January 2018-March 2022 were analyzed, and we achieved acceptable clinical outcomes. The in-hospital mortality and 30-day postoperative mortality were 15.4%, and the postoperative incidences of paraparesis (4%), stroke (4%), and AKI need hemodialysis (12%) were not particularly high, based on the limited patients sample size in short research period duration.

Keywords: cardiopulmonary bypass; hospital volume; kidney protection; left heart bypass; selective visceral perfusion; spinal cord protection; thoracoabdominal aortic aneurysm repair.

FIGURE 1

The main pipelines for cannulation and functional consumables connection in the LHB circuit. (A) The pipelines for cannulation, all diameters of the circuits are 3/8 inch, CP1 is the cut-point for connection of the cannulation of the inferior left pulmonary vein and the aortic cannulation. (B) The functional consumables connection pipelines of the LHB circuit. CP2 is the cut-point for the connection of a hard-shell reservoir, CP3 is the cut-point for a centrifugal pump, and CP4 for the heat exchanger. Line F can be occluded by a roller pump rather than a centrifugal pump in CP3. The port E and port E’ are a pair for an ultrafilter. Port I with a side hole is connected with a T-type adapter, which can be connected to a pressure monitor, and an arterial sampling connector. Both the port T1 in panel (A) and the port T1’ in panel (B) are connected with an oxygen saturation monitor or a connector. The port T2 in panel (A) and the port T2’ in panel (B) were connected with a Y-type connector (φ3/8” x3/8” x1/4”), and the 1/4-inch port of the connector is linked to the line for the selective visceral perfusion.

FIGURE 2

The pipelines for selective organ perfusion in the LHB circuit. (A) Line for selective visceral perfusion. (B) Line for selective kidney perfusion. (C) Y-type line connected to the T2 celiac axis for SMA and celiac axis perfusion or T4 to renal arteries for the selective perfusion. The line marked oblique dotted line is used for roller pumps.

FIGURE 3

The accessory pipelines for shed blood collection, rapid infusion and blood sampling. (A,B) Pipeline for the sucker. The line marked oblique dotted line is used for roller pumps. (C) Accessory pipelines for rapid infusion, S1 is the cut-point for connection of ultrafilter, and S2 is the cut-point for an arterial filter. The line marked oblique dotted line is used for roller pumps. (D) The accessory pipelines for blood sampling.

FIGURE 4

The assembled LHB circuit for perfusion. A, Hard-shell reservoir for priming and CPB reservation. B, centrifugal pump; C, heat exchanger; D, ultrafilter, E,F, roller pumps. C1-C5, Tube clumps; S1-S3, stop-flow clips.

FIGURE 5

The assembled reserved LHB circuit for the sucker and rapid-infusion perfusion. A, Hard-shell reservoir for shed filed blood collection by the pump suckers. B,C, roller pumps for suckers; D, roller pump for shifting blood to the rapid-infusion system; E, ultrafilter, F, arterial filter, G, rapid-infusion system.

FIGURE 6

The structure of modular multifunctional LHB circuit integrated with ultrafiltration and reserved pipelines for TAAA repair. The functions were indicted by different colors at the bottom of the figure.