Abrupt homeostatic responses to transient intracardiac occlusion during balloon valvuloplasty

[Anesthesia with transfemoral and transapical aortic valve implantation. Periinterventional management and hemodynamic observations]

Percutaneous transfemoral and transapical aortic valve implantations are novel procedures that often confront the anesthesiologist with bigger challenges than surgical aortic valve replacements using cardiopulmonary bypass. Due to old age and the presence of severe comorbidities including pulmonary vascular hypertension, most patients have a very high risk. Individual comorbidities and their severity are as important for the choice of the anesthetic technique as pharmacological cardiovascular therapy and communication during the respective phases of the intervention. Since severe hemodynamic alterations (cardiogenic shock, coronary ischemia, arrhythmias) and potential interventional complications (bleeding, ventricular and vascular injury) may occur, the authors routinely perform an extended cardiovascular monitoring. General endotracheal anesthesia may be advantageous even for transfemoral valve implantation and was not associated with a worse outcome. Following valve implantation a substantial increase in cardiac index, but also of all filling pressures was measured. Anesthesia coverage time for the first 100 cases averaged 263 min (+/- 96) for transfemoral and 297 (+/- 78) for transapical valve implantation, which appears greater than for conventional aortic valve replacement surgery, but it decreased significantly for transfemoral valve implantation over the course of interventions. Accordingly, the anesthesiologist, besides providing anesthesia and managing the airway, assumes responsibility for invasive cardiopulmonary monitoring, cardiovascular pharmacotherapy tailored to intervention phases, and "troubleshooting" in the event of complications for these still developing interventions.

Acute and delayed hormonal changes in mitral stenosis treated by balloon valvulotomy

The role of left atrial and aortic pressures on the secretion of the main hormones controlling blood volume is still subject to debate in humans. Because of increased mean left atrial pressure and decreased mean aortic pressure produced by balloon inflation in patients with mitral stenosis treated with balloon valvulotomy, the hormonal changes occurring acutely (group II of patients) were measured. The same studies (group I patients) were also performed 48 hours after this treatment, a period at which left atrial pressure permanently diminished. Inflation of the balloon resulted in a decrease in plasma renin activity and increases in plasma atrial natriuretic factor (ANF) and plasma arginine vasopressin (AVP). Forty-eight hours after balloon valvulotomy, which had produced a decrease in left atrial pressure, plasma ANF was lower (58.9 +/- 7.9 vs 95.3 +/- 11.9 pg/ml; p < 0.001), and plasma renin activity (2,575 +/- 533 vs 960 +/- 113 pg/ml/hour; p < 0.01), plasma angiotensin II (25.0 +/- 4.1 vs 9.3 +/- 1.3 pg/ml; p < 0.001) and plasma aldosterone (181.7 +/- 36.7 vs 139.9 +/- 19.8 pg/ml; p < 0.05) were higher than their respective control levels 24 hours before treatment of the stenosis. In contrast, plasma AVP (3.7 +/- 0.25 vs 4.4 +/- 0.31 pg/ml; p = 0.001) diminished moderately along with plasma osmolality (282.4 +/- 0.1 vs 286.2 +/- 0.6 mOsm/kg; p < 0.001). Urinary sodium excretion was also examined before and after balloon valvulotomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Baroreflex loading maneuvers do not suppress increased plasma arginine vasopressin in patients with congestive heart failure

Nonspecific baroreflex loading maneuvers such as head-down tilt readily suppress stimulated arginine vasopressin levels in normal humans. To test the hypothesis that the increased arginine vasopressin levels in patients with congestive heart failure would not respond normally to baroreflex loading, 12 patients with congestive heart failure had arginine vasopressin levels and osmolality determined in the supine position and after 15 min of 30 degrees head-down tilt. Arginine vasopressin was increased to 6.5 +/- 2.0 pg/ml at control measurement and did not decrease. Eight patients underwent further study after osmotic stimulation with mannitol. Mannitol increased osmolality from 287 +/- 9.2 to 294 +/- 7.8 mOsm/kg (p less than 0.001) and from 288 +/- 9 to 299 +/- 8.2 mOsm/kg (p less than 0.01) on two occasions. No significant suppression of arginine vasopressin was seen during head-down tilt after mannitol infusion compared with values in a time control period. These results are consistent with an abnormality in baroreflex suppression of arginine vasopressin secretion in chronic congestive heart failure and suggest that such a defect may contribute to long-term high levels of arginine vasopressin in this condition.

Percutaneous balloon aortic valvuloplasty. Acute and 30-day follow-up results in 674 patients from the NHLBI Balloon Valvuloplasty Registry

BACKGROUND

Percutaneous balloon aortic valvuloplasty has been used as a therapeutic option for relief of valvular stenosis. This study describes patients undergoing initial percutaneous aortic balloon valvuloplasty enrolled in the National Heart, Lung, and Blood Institute (NHLBI) Balloon Valvuloplasty Registry.

METHODS AND RESULTS

Extensive baseline procedural and postprocedural data were tabulated in 674 patients during a 24-month period. Functional status was captured using standard methods and an overall functional scoring system. Complications were defined and divided into procedural, acute (within 24 hours), in-hospital, and within 30 days of the procedure. The patient population was elderly and symptomatic, with 83% greater than 70 years of age. New York Heart Association functional class (FC) III or IV congestive heart failure (CHF) was present in 76%, syncope or presyncope was present in 34%, and Canadian Heart Association class III or IV angina was present in 23%. Using an overall functional scoring system (0-100), 54% exhibited scores less than 50. Comorbid disease was common. Forty-five percent possessed at least one serious noncardiac disability as a reason for valvuloplasty. Eighty percent of those seen by a cardiothoracic surgeon were believed inappropriate for aortic valve replacement. Hemodynamically, the aortic valve area increased from 0.5 +/- 0.2 cm2 to 0.8 +/- 0.3 cm2 (p less than 0.0001), accompanied by a fall in mean and peak aortic valve gradient from 55 +/- 21 and 65 +/- 28 mm Hg to 29 +/- 13 and 31 +/- 18 mm Hg, respectively (both p less than 0.0001). Small but significant increases were observed in cardiac output, heart rate, and mean aortic pressure with minor declines in the pulmonary artery (PA) systolic and left ventricular (LV) end-diastolic pressure. One hundred sixty-seven (25%) experienced at least one significant complication within 24 hours, and 211 (31%) experienced a significant complication before discharge. Complications before hospital discharge included the need for transfusion (23%), vascular surgery (7%), cerebrovascular accident (3%), other systemic embolus (2%), myocardial infarction (2%), acute tubular necrosis (1%), or cardiac surgery (1%). Seventeen (3%) patients died during the procedure; 16 of those were due to cardiac causes. By hospital discharge, there was an additional 52 total deaths; 37 were due to cardiovascular causes. Between hospital discharge and 30 days, 23 additional deaths occurred; 18 were due to cardiac disease. At 30 days, therefore, there was a grand total of 92 (14%) deaths; 71 (11%) were due to cardiovascular-related causes. Univariate and logistic regression analysis of mortality revealed that death was most frequent in patients suffering multiorgan failure and poor LV systolic function. Thirty-day mortality was associated with a predefined high-risk subset of hypotension and NYHA class IV CHF (risk ratio, 4.4), blood urea nitrogen (BUN) greater than 30 mg/dl (risk ratio, 3.7), use of an antiarrhythmic (risk ratio, 2.9), and cardiac output less than 3.0 l/min (risk ratio, 2.4). Of the survivors (86%) at 30 days, symptomatic improvement was generally present. Seventy-five percent experienced at least one functional class improvement in CHF, and 53% experienced at least a quartile improvement in overall functional status score.

CONCLUSIONS

These data reveal that percutaneous aortic balloon valvuloplasty in an elderly and debilitated population can be done with low mortality but substantial morbidity. Mortality is greatest in patients with multiorgan failure resulting from poor cardiac output. In patients with reasonably preserved LV function who are otherwise inappropriate surgical candidates because of comorbid factors, survival and early improvement in symptomatic status are frequently observed after percutaneous aortic valvuloplasty.