J Thorac Cardiovasc Surg 1995;109:812-814
© 1995 Mosby, Inc.
Is left heart bypass by cannulation of both femoral arteries an effective form of assisted circulation?
Hirofumi Ide, MDa,
Atsushi Yamaguchi, MDb
Department of Thoracic and Cardiovascular Surgery
Kyorin Medical School
Tokyo, Japana
Reply to the Editor:
We acknowledge Dr. De Paulis and his colleagues for their suggestion about the clinical application of the integrated cardioassist catheter (ICAC) method, a pulsatile left ventricular-aortic bypass method developed by us. Regarding clinical use, we have developed the ICAC as a left ventricular bypass system that can be easily applied in cases of left ventricular failure. It is used for conditions in which the intraaortic balloon pump is insufficient but the use of a conventional left ventricular assist device would be excessive. In developing this system, we intended to obtain a partial left ventricular bypass to provide short-term (about 1 week) support. As pointed out by Dr. De Paulis and colleagues, the dilemma is to obtain higher blood flow, a function essential for left ventricular bypass, and to reduce the outer diameter of the catheter for the prevention of the lower leg myonephropathic-metabolic syndrome, on the assumption that the insertion site is the femoral artery. The maximal flow rate was chosen on the basis of our experiences with percutaneous cardiopulmonary bypass in 30 consecutive patients and several cases of cardiac failure. Because most of the patients required the flow support at about 2 L/min, we set the maximum flow rate of the ICAC for clinical use at 2 L/min and prepared the catheter. Fig. 1 is a schematic illustration of ICAC for clinical use. The ICAC is made of polyurethane and is coated with heparin so as to decrease systemic heparin. Its inner shape is not oval. The actual inner diameter is about 15F, and the outer diameter is about 20F. As an in vivo study, a mock circulation study was conducted with heparinized human blood. The results obtained with our 90 cm catheter were similar to those obtained by Dr. De Paulis' group. We obtained the maximal flow rate of about 2 L/min with a pressure drop of 100 mm Hg and about 2.5 L/min at 150 mm Hg
1 (Fig. 2). At no time did the catheter collapse. In fact, in the in vitro study in dogs in which ICAC for human use was applied, 2 we confirmed that a flow rate of 2 L/min was obtained at an intracirculatory negative pressure of 100 to 140 mm Hg at the proximal portion of the centrifugal pump.
View larger version (20K):
[in this window]
[in a new window]
|
Fig. 2. Pressure-flow relationship. (From Yamaguchi A, Ide H, Kawahito K, et al. A New Method for Insertion and Use of the Integrated Cardioassist Catheter [ICAC] Left Ventricular Assist Device. Jpn J Artif Organs 1992;21:353-6; published with permission.)
|
|
The main point of our article 3 is to show by experiments in dogs that despite incomplete decompression (not the total decompression of the left ventricle reported previously by others 4) and also by left ventricular drainage, the peripheral circulation can be maintained and the left ventricle supported by adding electrocardiographically gated pulsatility. Thus pulsatility compensates for the limited maximal flow rate, which is the essential problem associated with our catheter. If the experimental results 3 are applied strictly and quantitively to the clinical situation, we have to admit the necessity of an ICAC maximal flow rate of 3 L/min, taking into consideration the safety margin pointed out by Dr. De Paulis. However, we have used the ICAC catheter for left ventricular bypass in two patients with profound left ventricular failure caused by ischemic heart disease (reference No. 5 and unpublished data), and the maximum flow rate of 2 L/min was obtained in both cases, similar to in vivo and in vitro experiments. With this flow rate, peripheral circulation could be maintained; moreover, echocardiographic findings revealed improvement in the left ventricular performance of the ischemic heart itself, and changes in serum free hemoglobin levels were within the acceptable range.
Because we have applied our catheter in only two cases so far, we cannot yet draw a definite conclusion as to whether the maximal flow rate of our ICAC for clinical use is acceptable. We want to investigate further the efficacy of the left ventricular bypass method by ICAC in a number of cases.
References
-
Yamaguchi A, Ide H, Kawahito K, et al. A new method for insertion and use of the integrated cardioassist catheter (ICAC) left ventricular assist device. Jpn J Artif Organs 1992;21:353-6.
-
Yamaguchi A, Ide H, Ino T, Adachi H, Mizuhara A, Kawahito K. Evaluation of a clinical model of integrated cardioassist catheter (ICAC). Jpn J Artif Organs 1993;22:628-31.
-
Ide H, Yamaguchi A, Ino T, et al. Evaluation of the pulsatility of a new left ventricular assist device—the integrated cardioassist catheter—in dogs. J THORAC CARDIOVASC SURG 1994;107:569-75.[Abstract/Free Full Text]
-
Rose EA, Marrin CAS, Bregman D, Spotnitz HM. Left ventricular mechanics of counterpulsation and left heart bypass, individually and in combination. J THORAC CARDIOVASC SURG 1979;77:127-37.[Abstract]
-
Yamaguchi A, Ide H, Ino T, et al. First clinical application of pulsatile trans-aortic left ventricular-femoral artery bypass (integrated cardioassist Catheter; ICAC). Jpn J Artif Organs 1994;23:47-51.
