Analysis of arterial intimal hyperplasia: review and hypothesis

which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background: Despite a prodigious investment of funds, we cannot treat or prevent arteriosclerosis and restenosis, particularly its major pathology, arterial intimal hyperplasia. A cornerstone question lies behind all approaches to the disease: what causes the pathology? Hypothesis: I argue that the question itself is misplaced because it implies that intimal hyperplasia is a novel pathological phenomenon caused by new mechanisms. A simple inquiry into arterial morphology shows the opposite is true. The normal multi-layer cellular organization of the tunica intima is identical to that of diseased hyperplasia; it is the standard arterial system design in all placentals at least as large as rabbits, including humans. Formed initially as one-layer endothelium lining, this phenotype can either be maintained or differentiate into a normal multi-layer cellular lining, so striking in its resemblance to diseased hyperplasia that we have to name it "benign intimal hyperplasia". However, normal or "benign " intimal hyperplasia, although microscopically identical to pathology, is a controllable phenotype that rarely compromises blood supply. It is remarkable that each human heart has coronary arteries in which a single-layer endothelium differentiates earl

Ultrafiltration in Cardiac Surgery

Cardiopulmonary bypass (CPB) may result in hemodilution and volume overload. Restoration of a normal hematocrit is important for post-operative myocardial performance. Diuretics, conventionally used in the post-operative period may be ineffective due to renal impairment or lead to electrolyte imbalance. Hollow-fiber hemofilters, made of an anisotropic polysulfone membrane (AMICON Diafilter) have been used for the ultrafiltration of blood in cardiac surgery during CPB. The hemofilter is inserted in the arterial line of the CPB. With this method ultrafiltration of the priming volume and restoration of the pre-operative hematocrit can be achieved and edema can be reversed. In our experiments, performed in dogs (n = 5) we removed 1 L of an ultrafiltrate of plasma water in 15 minutes without hemodynamic changes or electrolyte imbalance. In the same time hematocrit increased from 19 to 29% (p < 0.05) and protein concentration from 2.7 to 5.4 g/dl (p < 0.05). Simultaneous studies with Crlabelled RBC’s demonstrated that blood volume was not significantly altered from pre CPB values during ultrafiltration, suggesting that the origin of the removed ultrafiltrate was mainly from the extravascular space

Intraoperative internal mammary artery transit-time flow measurements: comparative evaluation of two surgical pedicle preparation techniques

OBJECTS: Myocardial revascularization is performed preferentially with internal mammary artery grafts. Pedicle preparation and pharmacologic vasodilatory treatment vary greatly. Objective measurements are difficult since peripheral and later coronary vascular resistance and possible competitive flow of the native bypassed coronary artery will influence the results significantly. Our objectives were: (1) measurement of internal mammary artery graft flow with the transit-time flow technique; (2) comparison of two surgical take-down techniques (skeletonizing vs standard pedicle preparation); (3) quantitation of transit-time flow compared to the free pedicle flow and (4) the vasodilatory effect of papaverine on internal mammary artery flow. METHOD: Consecutive elective cases of coronary artery bypass grafting, performed by two surgeons using routinely either skeletonizing of the internal mammary artery (group A, n = 10) or classical pedicle preparation technique (group B, n = 10), were studied prospectively. Anesthesia, cardiopulmonary bypass and operative data were otherwise comparable; likewise, hemodynamic parameters showed no statistical differences between the two groups. Transit-time flow (CardioMed, Medi-Stim, Norway) was measured at the following time points: beginning (1) and end of take-down (2); after papaverine soaking: before (3) and on cardiopulmonary bypass (4); free flow into a beaker (5); after anastomosis; on (6) and off cardiopulmonary bypass (7). RESULTS: Measurement of mean flow showed the following results: (1) severe vasoconstruction of the internal mammary artery was detected in both groups regardless of the preparation technique (occurring earlier in group A); (2) papaverine soaking caused a moderate flow increase (up to 40%); (3) with corresponding cardiopulmonary bypass flow (4.4 vs. 4.1 l/min in group B) a higher free flow in group A was evident (67.7 vs. 50.7 ml/min); (4) after coronary grafting, transit-time flow showed no significant differences between the two groups and (5) using a 3 mm probe, a linear correlation was demonstrated between transit-time flow and simultaneously measured free flow (r = 0.89). CONCLUSION: Intraoperative transit-time flow measurement is a reliable method for assessing internal mammary artery and coronary artery bypass flow; considering the simple technical application, the procedure may be regarded as a valuable instrument of quality control

Outcome of survivors of accidental deep hypothermia and circulatory arrest treated with extracorporeal blood warming

BACKGROUND: Cardiopulmonary bypass has been used to rewarm victims of accidental deep hypothermia. Unlike other rewarming techniques, it restores organ perfusion immediately in patients with inadequate circulation. This study evaluated the long-term outcome of survivors of accidental deep hypothermia with circulatory arrest who had been rewarmed with cardiopulmonary bypass. METHODS: Deep hypothermia (core temperature, &lt;28 degrees C) with circulatory arrest was found in 46 of 234 patients with accidental hypothermia. In 32 of the 46 patients, rewarming with cardiopulmonary bypass was attempted, resulting in 15 long-term survivors. In most of these patients, deep hypothermia developed after mountaineering accidents or suicide at tempts. After an average (+/-SD) of 6.7+/-4.0 years of follow-up, we obtained the patients' medical histories and performed neurologic and neuropsychological examinations, neurovascular ultrasound studies, electroencephalography, and magnetic resonance imaging of the brain. RESULTS: The average age of the patients was 25.2+/-9.9 years; seven were female and eight were male. The mean interval from discovery of the patient to rewarming with cardiopulmonary bypass was 141+/-50 minutes (range, 30 to 240). At follow-up there were no hypothermia-related sequelae that impaired quality of life. Neurologic and neuropsychological deficits observed in the early period after rewarming had fully or almost completely disappeared. One patent had cerebellar atrophy on magnetic resonance imaging with mild clinical signs, a condition that may have been caused by hypothermia. Other clinical abnormalities were either preexisting or due to injuries not related to hypothermia CONCLUSIONS: This clinical experience demonstrates that young, otherwise healthy people can survive accidental deep hypothermia with no or minimal cerebral impairment, even with prolonged circulatory arrest. Cardiopulmonary bypass appears to be an efficacious rewarming technique

Retransfusion des Thoraxdrainageblutes: qualitative Analyse. [Retransfusion of thoracic drainage blood: qualitative analysis]

In a prospective randomized study 10 patients received their shed mediastinal blood after elective coronary artery bypass surgery and were compared to 10 control patients without retransfusion. The quality assessment can be summarized as follows (mean +/- 1 SD): 1. Hemoglobin concentration of the shed blood was 9.6 +/- 1.45 g/dl. 2. The energy rich phosphate compounds of the shed blood erythrocytes were 2.6 +/- 0.8 mumol/gHb ATP (70% of the patients preoperative value) and 14.8 +/- 4.2 mumol/gHb 2.3-DPG (normal). 3. Proteins, immunoglobulins and especially albumin in the shed blood were not significantly different from the patients own values. 4. No electrolyte changes, safe for a slight increase in potassium (5.7 +/- 0.7 mmol/l). 5. The activated clotting time of the patient did not change during retransfusion. 7. Plasma free hemoglobin was elevated to 211.1 +/- 44.3 mg/dl in the shed blood; however, no significant increase could be noted in the retransfused patients and no hemoglobinuria occurred. Postoperative retransfusion of shed mediastinal blood is a simple and safe method of autologous transfusion early after cardiac surgery and should be combined with other methods of blood salvage. The qualitative advantages of blood retransfusion consist in the absence of storage damage and in the preservation of autologous proteins and immunoglobulins

Catheter tip force required for mechanical perforation of porcine cardiac chambers

Catheter manipulation during ablation procedures can produce injury and tamponade. We evaluated the mechanical forces required to perforate a porcine heart with an ablation catheter