Microcirculation of a bulbar conjunctiva in calves with the total artificial heart: results of a long-term study

2003

In the short historical review the principal technical and pathophysiological approaches of the Czech total artificial heart (TAH) research are emphasized. Survival was endangered by arterial and venous hypertension, especially the central venous pressure (CVP) increase, mineralization of driving diaphragms, thromboembolization, and infection. By the appropriate combination of antihypertensive, antimineralization, and anticoagulation treatment and of measures against infection, the survival of the experimental calves was increased (the longest one was 314 days of pumping). Technical and constructional improvement of the blood pumps was another cause of successful experiments. All details are issued in the references.

Section: Resultsmentioning

confidence: 70%

Total Artificial Heart: The Adaptation and Pathophysiological Deviations in the Recipient

Vasků

2003

“…Especially in the liver, the changes were mainly caused by the increased CVP with concomitant subsequent stasis in the liver microcirculation with hypoxic damage of the hepatic tissue. The pathogenesis of the CVP increase in the TAH animals has been published elsewhere, and based on this pathogenetic background, we also could perform an essentially successful pathophysiological treatment (5,7,(10)(11)(12). Due to this treatment and also partly due to the systemic antimineralization treatment aimed at the prevention of mineralization of driving diaphragms, we could substantially increase the length of survival (1,2).…”

Section: Discussionmentioning

confidence: 91%

“…The antihypertensive treatment was performed because of our observation of the increased arterial hypertension, and especially of venous hypertension, during a long‐term survival where marked liver damage and partial kidney damage was observed. The detailed methods of application of the antihypertensive treatment also were described in previous publications (5,7,10–12). Therefore, the description of the methods used for the EM evaluation is given in this study.…”

Section: Methodsmentioning

confidence: 99%

Electronmicroscopic Changes in Selected Vital Organs After Long‐Term Total Artificial Heart Pumping in Animal Experiments

Vasků

2000

Electronmicroscopic (EM) evaluation of selected vital organs (liver, kidney, lung) informs us about otherwise hardly detectable changes during total artificial heart (TAH) pumping. In our experiments, we compared 2 groups of long-surviving animals in which the TAH TNS-BRNO pneumatic device was implanted (TNS-BRNO-II and VII in 45 experiments, TNS-BRNO-III in 1 experiment, and TNS-BRNO-VIII in 1 experiment). In 4 experiments, the Rostock TAH (NABEL, TAH Research Center, Rostock, Germany) was implanted. One group of 22 animals with an average survival of 162 days (the longest, 293 days) was submitted to an antihypertensive treatment; another 1 of 29 calves with an average survival of 98 days (the longest, 173 days) was untreated. The evaluation was performed using a scale (0 to 3) based on very precisely fixed criteria. EM pathologic changes documented various stages of ischemic damage. Except for the liver, no significant difference was found between both groups, despite the substantially prolonged survival in the treated group. Very important was the general state of mitochondria, endoplasmic reticulum, and nucleus. Further, the state of glomerular podocytes in the kidney and the state of interalveolar septa and of pneumocytes constituting the air-blood barrier for gas exchange in the lungs are especially important. In some animals of both groups, the EM findings were completely normal, especially in the lung.

“…Microcirculation of the bulbar conjunctiva was studied in 2 goats (code numbers 0020 and 0030, surviving 16 and 54 days, respectively) with undulation pump total artificial heart (UPTAH) and in 10 control goats using the method of conjunctival angioscopy with microphotograph records (4). The pictures were obtained by a specially adjusted Nikon camera with a flashlight system.…”

Section: Methodsmentioning

confidence: 99%

Microvessels of Bulbar Conjunctiva in UPTAH Goats

Vaškuo²,

Baba

et al. 2003

Aiming to observe directly the microcirculation after total artificial heart (TAH) implantation, we performed a long-term follow-up in 2 goats using conjunctival angioscopy. A short segment of parallel arteriole and venule was photographed and analyzed on computer picture program (magnification 40x). Three main parameters were measured: arteriole diameter, venule diameter, and arteriovenous ratio (A/V ratio). The intrathoracically implanted TAH was the undulation pump total artificial heart (UPTAH) with cardiac output of 100 ml/kg/min. To stabilize the peripheral hemodynamics a 1/R biofeedback control system was used. Our results provided only elementary data about morphology of bulbar microvessels. The main finding was the tendency to general vasoconstriction, more intensive on the venous side (*P < 0.05 in one goat). We did not observe any pathological shapes (e.g., tortuosities, varicosities, or sludge); this result could be attributed to the high effectivity of 1/R control method. These preliminary results should be considered only as an attempt to apply the widely used clinical method of conjunctival angioscopy to the conditions of TAH.