Sergio Moran

Renal function and cardiopulmonary bypass : effect of perfusion pressure

Controversy continues as to whether hypotension during cardiopulmonary bypass (CPB) impairs intraoperative and postoperative renal function. Therefore, 21 patients with normal renal function (plasma creatinine less than 1.2 mg/dL, creatinine clearance greater than 70 mL/min), aged 50 to 70 years, without associated pathology, scheduled for elective coronary surgery were studied prospectively. Patients were randomized into two groups: group 1 included 14 patients whose arterial blood pressure during CPB was left untreated, and group 2 consisted of 7 patients who received phenylephrine to maintain their arterial pressure above 70 mmHg. Plasma and urine creatinine, sodium, potassium, and osmolality were measured preoperatively, intraoperatively and postoperatively. Creatinine, osmolal and free water clearances, and excreted sodium fraction were calculated. Plasma creatinine remained normal throughout the study in all patients. Creatinine clearances were similar preoperatively (101.9 +/- 36.7 in group 1 and 120.6 +/- 50.7 mL/min in group 2). In group 1, creatinine clearance decreased during CPB to 88.7 +/- 39.7 mL/min, whereas in group 2 it increased to 157.6 +/- 79.5 mL/min; the difference between groups was significant. Early postoperatively, there was no difference: 136.2 +/- 86.6 mL/min in group 1 and 100 +/- 21.4 mL/min in group 2. One week postoperatively, values were 100.5 +/- 37.9 and 101.9 +/- 18.4, respectively. There was a significant correlation between the creatinine clearance and perfusion pressure intraoperatively, but not postoperatively. Osmolal clearance also correlated with perfusion pressure intraoperatively, but it was significantly lower in the phenylephrine group postoperatively. Postoperative renal function was normal in all patients; no deleterious effect of a low arterial pressure during bypass could be identified.

Effects of extracorporeal circulation on renal function in coronary surgical patients

We prospectively studied perioperative changes of renal function in 12 previously normal patients (plasma creatinine <1.5 mg/dL) scheduled for elective coronary surgery. Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured with inulin and125 I-hippuran clearances before induction of anesthesia, before cardiopulmonary bypass (CPB), during hypo- and normothermic CPB, after sternal closure, and 1 h postoperatively. Renal and systemic vascular resistances were calculated. Urinary N-acetyl-beta-D-glucosaminidase (NAG) and plasma and urine electrolytes were measured, and free water, osmolal, and creatinine clearances, and fractional excretion of sodium and potassium were calculated before and after surgery.125 I-hippuran clearance was lower than normal in all patients before surgery. During hypothermic CPB, ERPF increased significantly (from 261 +/- 107 to 413 +/- 261 mL/min) and returned toward baseline values during normothermia. GFR was normal before and after surgery and decreased nonsignificantly during CPB. Filtration fraction was above normal before surgery and decreased significantly during CPB (0.38 +/- 0.09 to 0.18 +/- 0.06). Renal vascular resistance (RVR) was high before surgery and further increased after sternotomy (from 18,086 +/- 6849 to 30,070 +/- 24,427 dynes centered dot s centered dot cm-5), decreasing during CPB to 13,9647 +/- 14,662 dynes centered dot s centered dot cm-5. Urine NAG, creatinine, and free water clearances were normal in all patients both pre- and postoperatively. Osmolal clearance and fractional excretion of sodium increased postoperatively from 1.54 +/- 0.06 to 12.47 +/- 11.37 mL/min, and from 0.44 +/- 0.3 to 6.07 +/- 6.27, respectively. We conclude that renal function does not seem to be adversely affected by CPB. Significant functional alterations, such as decreased ERPF and increased RVR, were found before and during surgery, preceding CPB. These periods could contribute to postoperative renal dysfunction. (Anesth Analg 1995;81:446-51)

Renal protection in patients undergoing cardiopulmonary bypass with preoperative abnormal renal function

We prospectively studied the effects of renal protection intervention in 17 patients with preoperative abnormal renal function (plasma creatinine >1.5 mg/dL) scheduled for elective coronary surgery. Patients were randomized to either dopamine 2.0 micro g [center dot] kg-1 [center dot] min-1 (Group 1

Association of Remote Hypertension in Pregnancy With Coronary Artery Disease. A Case-Control Study

Because hypertensive pregnancies have been associated with increased cardiovascular disease, we aimed to identify whether angiographically characterized coronary artery disease differed in women with previous normotensive pregnancies or hypertensive pregnancies (HPs). The study group included 217 parous women, aged 60.9±9.2 (SD) years, who required coronary angiography between January 2006 and December 2007, 36.8±9.9 and 28.8±10.5 years after their first and last pregnancy, respectively; 146 had normotensive pregnancies and 71 had ≥1 HP, according to a questionnaire including reproductive history and cardiovascular risks. Body mass index, smoking, and frequency of diabetes were similar in both groups. Chronic hypertension (93% versus 78%; P=0.007), hyperlipidemia (82% versus 69%; P=0.049), and premature familial cardiovascular disease (42% versus 20%; P=0.001) prevailed in HPs. Participants with HPs were younger (58.9±8.3 versus 61.9±9.6 years; P=0.025) than participants with normotensive pregnancies. Although 49% of all participants had hemodynamically significant coronary artery disease (≥70% stenosis), no differences were observed between groups in the number of stenotic arteries; however, their number increased by 28% and 22% over a 10-year period in HPs and normotensive pregnancies, respectively (P=0.034). Multivariate analysis showed that HPs had a nonsignificant risk of having coronary artery disease (odds ratio: 1.21; 95% CI: 0.64 to 2.28), and being a current smoker (odds ratio: 4.13; 95% CI: 1.85 to 9.25), a diabetic (odds ratio: 2.29; 95% CI: 1.85 to 9.25), or having a family history of premature cardiovascular disease (odds ratio: 2.34; 95% CI: 1.17 to 2.39) significantly increased the risk of coronary artery disease. This study demonstrates that women with HPs have earlier coronary disease, probably related to intermediate cardiovascular risks that have a gestational expression.

Arterial pressure-flow relationship in patients undergoing cardiopulmonary bypass.

We determined the arterial pressure-flow relationship experimentally by means of step changes of blood flow in 30 adult patients undergoing cardiopulmonary bypass (CPB). Anesthesia technique was uniform. CPB was nonpulsatile; hypothermia to 25-28 degrees C, and hemodilution to 18%-25% hematocrit were used. During stable bypass, mean arterial pressure was recorded first with blood flow 2.2 L [centered dot] min (-1) [centered dot] m-2. Flow was then increased to 2.9 L [centered dot] min (-1) [centered dot] m-2 for 10 s and reverted to baseline for 1 min. Then it was decreased to 1.45 L [centered dot] min-1 [centered dot] m-2 for 10 s, and reverted to baseline for 1 min. Subsequently, it was decreased to 0.73 L [centered dot] min-1 [centered dot] m-2 for 10 s and then reverted to baseline. Similar sets of measurements were repeated after 0.25 mg of phenylephrine and once the patient was rewarmed. The pressure-flow function was individually determined by regression, and the critical pressure estimated by extrapolation to zero flow. All patients had zero-flow critical pressure during hypothermia, with a mean value of 21.8 +/- 6.4 mm Hg (range 8.8-38.9). It increased after 0.25 mg phenylephrine to 25.4 +/- 7.2 mm Hg (range 12.2-43.9, P < 0.001). During normothermia, critical pressure was 21.2 +/- 5 mm Hg (range 13.4-30.9), not significantly different from hypothermia. During hypothermia, the slope of the pressure-flow function (i.e., resistance) was 14.9 +/- 3.5 mm Hg [centered dot] L-1 [centered dot] min-1 [centered dot] m-2 (range 7.6-22.1). It increased significantly (P < 0.001) after phenylephrine, to 19.7 +/- 6.2 mm Hg [centered dot] L-1 [centered dot] min-1 [centered dot] m-2 (range 11.4-40.5), and returned to 15.4 +/- 3.4 mm Hg [centered dot] L-1 [centered dot] min-1 [centered dot] m-2 (range 10.1-24.2) during normothermic bypass. Systemic vascular resistance appeared to vary reciprocally with blood flow, although this finding may represent a mathematical artifact, which can be avoided by using zero-flow critical pressure in the vascular resistance equation. (Anesth Analg 1997;84:958-63)

Successful anesthetic management of a patient with hypokalemic familial periodic paralysis undergoing cardiac surgery.

Hypokalemic familial periodic paralysis is a rare disease, with obvious anesthetic implications. We report a case of a patient with known hypokalemic familial periodic paralysis, who required coronary revascularization. An impending episode of paralysis on the Ist postoperative day was aborted by aggressive management of plasma potassium concentration

Acetylcholinesterase changes in hearts with sinus rhythm and atrial fibrillation

1. Clinical and experimental evidence suggest that changes in the autonomic tone play a role in the pathogenesis of atrial fibrillation. 2. We have studied the distribution of molecular forms of acetylcholinesterase (AChE) in atrial biopsies obtained from individuals without arrhythmias and in patients with atrial fibrillation. 3. Analysis of the distribution of globular and asymmetric AChE forms, showed a decrease in the amount of the globular forms of biopsies taken from atria during fibrillation. 4. This study is the first attempt to characterize the molecular forms of AChE in the human heart of patients with sinus rhythm and chronic atrial fibrillation.

Resultados alejados de la cirugía reconstructora de la insuficiencia mitral

Background: Surgical repair is the procedure of choice for mitral insufficiency since it preserves better left ventricular structure and function. Aim: To assess the long term clinical and echocardiographic results of mitral valve reconstructive surgery. Material and methods: A review of clinical and echocardiographic data of 68 patients (34 male, age range 17 to 82 years), subjected to surgical mitral valve repair between December 1991 and March 1998. Preoperative functional capacity of these patients was 2.96 ± 0.7. Surgical repair was assessed using transesophagic echocardiography in all subjects. Results: The etiology of mitral insufficiency was degenerative in 43 patients, rheumatic in 10, infectious in 6, ischemic in 5 and miscellaneous in 4. The most frequent pathological findings were dilatation of the mitral ring in 42% of patients, chordae tendinae rupture in 32% and enlargement in 24%. A mitral anuloplasty was done in 90% of patients, a cuadrilateral resection of posterior leaflet in 52% and chordae tendinae transference in 12%. An additional surgical procedure was done in 34% of subjects. Three patients died during hospitalization (4.4%). During the follow up of 36.5 ± 22.3 months, five patients died and one required a mitral valve replacement. The actuarial survival probability was 95.3 ± 2.6% at one year and 83.5 ± 6.5% at five years. The reoperation free survival was 100% at one year and 97.4 ± 2.5% at five years. At the end of follow up the functional capacity improved to 1.25 ± 0.4. Echocardiography showed absence of mitral insufficiency in 48.4% of patients, minimal, mild and moderate insufficiency in 35.5, 14.5 and 1.6% of patients respectively. Conclusions: Surgical valve reconstruction in mitral insufficiency has satisfactory long term results and should be the procedure of choice for eligible patients.

Surgical Removal of Entrapped Endocardial Leads Without Using Extracorporeal Circulation

Of 267 patients having a tined endocardial lead implanted from 1978 to December 1983, three (1.1%) developed pulse generator pocket infection. Proper treatment of this complication involves removal of the pulse generator, continued external pacing via the implanted lead, pocket drainage and administration of specific antibiotics until the infected area clears. In two patients, the electrode could not be removed by traction. A sternotomy was performed, the pericardium was opened, the endocardial electrode was located by palpation, and a purse string suture (PSS) was prepared around it on the right ventricular wall. A new myocardial electrode with its corresponding generator was then implanted to reestablish pacing. Through the PSS the myocardium was incised, the distal end of the endocardial lead was exteriorized and severed, and the PSS was tied. The remaining lead was withdrawn proximally and the surgical wounds were closed. The results of this procedure have been been excellent, allowing the removal of the entrapped leads, with continuous pacing and without the need for extracorporeal cir culation.

Characterization of acetylcholinesterase from human heart auricles: Evidence for the presence of a G-form sensitive to phosphatidylinositol-specific phospholipase c

1. Acetylcholinesterase (AChE) is an important enzyme of the cholinergic system in mammals. 2. We report here the subcellular association of the AChE molecular forms in the normal human heart auricle. 3. Both globular (G) and asymmetric (A) forms were identified using velocity sedimentation and sequential extraction procedures. 4. G forms corresponds to 84% and A forms account for 16% of the total AChE activity. 5. Of G forms 64% of AChE activity correspond to the G1 monomer and of the A forms the class I-A account for 80% of AChE activity. 6. In addition, treatment of the cardiac membranes with the enzyme phosphatidylinositol-specific phospholipase c (PIPLC) results in the solubilization of AChE activity. 7. This means that a G2 AChE dimer with a glycolipid anchoring domain is present in the human heart.