A novel technique for intraaortic balloon pump placement via the left axillary artery in patients awaiting cardiac transplantation

In order to circumvent the problems associated with long-term femoral intraaortic balloon pump (IABP) placement we have developed and used a new technique of IABP placement. Over the past three years 13 patients awaiting cardiac transplantation have had placement of IABP via a vein cuff sewn to the left axillary artery. Thirteen patients have undergone IABP placement using this technique. The average duration of IABP support was 37 days (range 10-86 days). Ten patients were successfully transplanted. All patients were allowed to sit, stand and ambulate with assistance. No neurologic complications occurred. There were no episodes of sepsis related to balloon or insertion site. No patient had limb ischemia during IABP counterpulsation. Left axillary artery IABP insertion via a vein cuff portal is a straightforward technique with minimal complications. This method serves as a bridge to cardiac transplantation in a gravely ill group of patients while preserving patient mobility during the waiting period for a donor heart.

Hemodynamics and aneurysm development in vascular allografts

PURPOSE

Mechanical and immunologic factors may play a role in the development of native arterial and biologic graft aneurysms. We developed an experimental rat aortic allograft aneurysm model in which segments of infrarenal aorta were transplanted between hypertensive and normotensive rats to study these factors in this model.

METHODS

Aortic allografts and autografts were inserted into spontaneously hypertensive (SHR) and normotensive Wistar Kyoto (WKY) rats. Effects of immunologic and antihypertensive therapy were evaluated. Graft diameters were followed up with magnetic resonance imaging and at harvest. Direct-pressure measurements were taken and dp/dtmax (force of ventricular contractions) was calculated before harvest.

RESULTS

Autografts remained isodiametric and maintained their histologic architecture. Aneurysmal dilation of transplanted segments occurred in SHR host allografts but not in WKY host allografts. Histologic examination of all allograft specimens noted a rejection reaction characterized by inflammatory cell infiltration and medial smooth muscle cell loss. Antigenic enhancement accelerated aneurysm development in SHR hosts but had no significant effect on WKY hosts. Rates of allograft enlargement and final allograft diameters were similar in antihypertensive treated and untreated SHR hosts. The dp/dtmax in untreated SHR hosts was greatest and differed significantly from that in the WKY rats but only marginally from that in treated SHR hosts.

CONCLUSIONS

Immunologic rejection but not abnormal hemodynamics is necessary for development of allograft aneurysm in this model.

Spontaneously hypertensive and Wistar Kyoto rats are genetically disparate

Spontaneously hypertensive rats (SHR) are one of the most common animal models used to study essential hypertension in humans. Because SHR and normotensive Wistar Kyoto (WKY) rats were both established from the same parental, normotensive Wistar stock, WKY animals have been used almost exclusively as control animals in studies of SHR. Recently, the suitability of WKY rats as normotensive controls for SHR has been challenged. To establish whether or not SHR and WKY rats share the same immunologic backgrounds, we initially performed a series of skin grafting experiments on these animals. In all cases, grafts of SHR donor skin to WKY recipients and of WKY donor skin to SHR recipients resulted in complete rejection within 7 to 10 days. In addition, grafts of WKY donor skin to other WKY recipients resulted in graft rejection. By contrast, skin grafts between SHRs were always accepted. To further characterize the genetic distinctions between SHR and WKY rats, allelic profiles based on a series of immunologic and biochemical markers were established for each strain. These findings clearly establish that SHR and WKY rats differ at the major histocompatibility complex, in specific blood group antigens, and in a panel of isozymic markers. Moreover, whereas SHRs have the same genetic profiles irrespective of source, some colonies of WKY rats are outbred, as judged by their variant allelic profiles.