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Biomedical subjects

G M Palatianos

Publications and source records attributed to G M Palatianos.

At least 19 recordsLinked to original sources

Multicenter study of stentless valve replacement in the small aortic root.

OBJECTIVE: A clinical study was conducted to evaluate the results of stentless porcine valves in patients with a small aortic root (19- and 21-mm aortic anulus). METHODS: Of 567 patients, from 4 surgical institutions, 171 patients (30.1%) had a small aortic root, comprising 163 cases with calcified aortic stenosis and 8 cases with predominant valvular insufficiency. Sixty patients had associated mitral or coronary lesions. Mean age was 72 +/- 4.2 years. Forty-seven patients with a small aortic root had a 19-mm anulus, and 124 patients had a 21-mm anulus. The body surface area was, respectively, 1.55 +/- 0.2 m2 and 1.78 +/- 0.45 m2. Hemodynamic evaluation of the stentless valve comprised serial measures of mean gradients, effective orifice area, and left ventricular mass reduction. Complication rates for secondary events were evaluated over a 6-year period. RESULTS: The hospital mortality rate was 3.5%. The mean gradients after the first year were 9 +/- 2 mm Hg and 6 +/- 1.7 mm Hg in patients with a 19-mm and a 21-mm anulus, respectively. Effective orifice area was 1.45 +/- 0.3 cm2 and 1.72 +/- 0.4 cm2. Gradients and surfaces remained stable throughout the study period. Aortic regurgitation was zero to trace. Left ventricular mass at discharge and at 1 year were, respectively, 296 +/- 127 g and 215 +/- 102 g for patients with a 19-mm anulus and 281 +/- 75 g and 236 +/- 15 g for patients with a 21-mm anulus. CONCLUSIONS: Stentless valves are a suitable device for elderly patients with small aortic roots, which leave only mild residual obstruction.

Aged↗

Unexpected cardiac arrest after cardiac surgery: incidence, predisposing causes, and outcome of open chest cardiopulmonary resuscitation.

STUDY OBJECTIVES: To assess the incidence of acute mechanical causes precipitating sudden cardiac arrest in cardiac surgery patients during the immediate postoperative period. In addition, we report the success rate of cardiopulmonary resuscitation (CPR) in which open-chest CPR was employed at an early stage of the resuscitation effort. METHODS: Data on all cardiac surgical patients who suffered a sudden cardiac arrest during the first 24 h after surgery were collected prospectively. CPR consisted of conventional closed-chest CPR initially and was followed within 3 to 5 min, if needed, by open-chest CPR. RESULTS: Of 3,982 patients undergoing cardiac surgery over a 30-month period, 29 patients (0.7%) had a sudden cardiac arrest. Of these, 13 patients (45%) were successfully resuscitated with closed-chest CPR, 14 (48%) with open-chest CPR, and 2 (7%) died despite closed- and open-chest CPR. Four CPR survivors died subsequently in the ICU, yielding an overall hospital discharge rate of 79%. Perioperative myocardial infarction was the underlying cause of sudden cardiac arrest in 14 patients (48%), and mechanical impediments to cardiac function (tamponade or graft malfunction) in another 8 (28%) patients; in the remaining 7 patients (24%), no underlying cause was found. The length of ICU stay was 6+/-1 (mean+/-SE) days. None of the patients developed wound infection and all were neurologically intact at hospital discharge. CONCLUSION: Mechanical factors account for a substantial portion (28%) of causes of sudden cardiac arrest occurring in hemodynamically stable patients during the immediate postoperative period. This high incidence, in conjunction with the high survival rate achieved by open CPR, supports an early approach to open-chest CPR in this group of patients.

Cardiac Surgical Procedures↗

Comparative thrombogenicity of pacemaker leads.

To evaluate the thrombogenicity of transvenous silicone and polyurethane pacemaker leads, 9 of 12 anesthetized Yorkshire pigs (27-32 kg) were implanted with silicone (n = 5) or polyurethane (n = 4) pacemaker leads via a femoral vein. The remaining three pigs served as controls. All 12 pigs were injected with autologous indium-111 labeled platelets (300-420 muCi) 24 hours before anesthesia induction. The pigs were monitored for 3 hours under a gamma camera. Radioactivity in blood and lead segments was measured with a gamma counter. Platelet deposits were denser on silicone leads (441.58 +/- 915.0 to 2.19 +/- 2.07) than on polyurethane leads (1.21 +/- 1.33 to 0.27 +/- 0.14) (P > 0.05). Denser platelet deposits were detected at the tip of all leads. Density of platelet deposits declined from tip to distal segments in silicone leads. The percentage of injected platelet radioactivity in the lungs of pigs with either silastic leads (12.9 +/- 2.3%) of polyurethane leads (10.1 +/- 2.2%) was higher than in the controls (4.6 +/- 0.5%) (P < 0.05). This difference indicates thrombus formation and embolization in the lungs early after lead implantation. Thrombogenicity of polyurethane leads may be lower than that of silicone leads.

Animals↗

Transaortic resection of the subaortic membrane. Treatment for subvalvular aortic stenosis.

In an attempt to better understand congenital subaortic stenosis, we reviewed 19 consecutive pediatric patients undergoing surgery for this problem between 1973 and 1984. Preoperative cardiac catheterization demonstrated subvalvular stenosis in all patients and associated anomalies in 11 patients. All patients underwent transaortic resection of the subaortic membrane. Five patients underwent concurrent additional cardiac procedures. An 8-month-old infant with multiple cardiac anomalies was the only operative mortality. Follow-up extended to 16 years, with a mean of 6.9 years. In five symptomatic patients, cardiac catheterization revealed a mean systolic pressure gradient of 33.0 +/- 31.94 mm Hg 24.7 months (mean) after surgery. Two of these patients (11.1 percent of survivors) required reoperation. Twelve of the remaining 13 asymptomatic patients underwent echocardiographic follow-up, and 4 were found to have recurrent stenosis with 1 requiring surgery (5.6 percent of survivors). Our experience shows that transaortic resection of the subaortic membrane is an acceptable treatment for subvalvular aortic stenosis, but is associated with a high incidence of recurrence requiring reoperation (3 of 18 or 16.7 percent). Consequently, it is reasonable to consider the role of alternative therapies which may help prevent recurrence in selected cases.

Adolescent↗

Sequential internal mammary artery grafts for coronary artery bypass.

From 1985 to 1990, 145 patients underwent isolated coronary artery bypass with one (n = 128) or both (n = 17) internal mammary arteries (IMAs) used as sequential bypass grafts. All but 2 patients had angina pectoris preoperatively. A total of 162 sequential IMA grafts were constructed bypassing two (n = 152) or three (n = 10) coronary artery sites as in situ (n = 132) or free (n = 30) grafts. In 12 patients, one IMA was used as a nonsequential graft. Thirty-day mortality was 2.8% (n = 4 patients). Perioperative myocardial infarction occurred in 1 patient (0.7%). Only two sequential IMA grafts failed. Both were used to bypass coronary arteries 1.00 mm in diameter. Mean follow-up was 31 months (range, 6 months to 4.2 years). There were three late deaths. Of 136 survivors followed-up, 121 (89%) were free of angina. Postoperative rotational thallium 201 tomography was done in 73 patients. Myocardial ischemia was detected in 11 diabetic patients (15.1%), but corresponded to a sequential IMA graft in 4 (5.5%) and to nonsequential and venous grafts in 10 patients (13.7%). Coronary revascularization with sequential IMA grafts was safe and effective.

Adult↗

Long-term surgical results in sudden death syndrome associated with cardiac dysfunction after myocardial infarction.

To evaluate the surgical results in patients with inducible ventricular tachyarrhythmias due to coronary disease and left ventricular dysfunction, the authors reviewed their experience in 170 patients who had survived one or more cardiac arrests after myocardial infarction and were unresponsive to drug therapy based on electrophysiologic studies (EPS). There were nine operative deaths (5%). Based on intraoperative EPS, surgical remodeling of left ventricular dysfunction (aneurysm resection, infarct debulking, and septal reinforcement) with map-guided cryoablation and coronary artery bypass graft was performed in 34 patients (group A), and left ventricular remodeling and coronary artery bypass graft without guided endocardial resection was performed in 25 patients (group B). Forty-three patients (group C) had coronary artery bypass graft with implantation of an automatic implantable cardioverter defibrillator (AICD). Group D (68 patients) received AICD only. After operation, based on EPS results, four patients in group A (12%) and three patients in Group B (15%) required AICD implantation. Overall survival at 6 years was 65%, 48%, 85%, and 58% in patient groups A, B, C, and D, respectively (p = not significant). During follow-up in group A patients, none died suddenly and none needed AICD. In group B, two patients required AICD 3 and 5 years later, and five patients died suddenly. The incidence of sudden death was 2.3%/patient/year and 3.5%/patient/year after AICD implantation (groups C and D). At 6 years, cardiac-event-free survival was 80% and 70% for groups A and B and 38% and 24% for groups C and D, respectively (p less than 0.001). Patients receiving map-guided ablative procedures had significantly improved cardiac-event-free survival rates.

Adult↗

George N. Papanicolaou, M.D. Father of modern cytology. A 30-year commemorative.

Thirty years have passed since the death of the renowned Dr. George N. Papanicolaou, a man of conviction and discoverer of the Pap smear. Despite difficulties and opposition he remained persistent and developed a method for early cancer detection. Subsequently, use of the Pap smear has resulted in a 70% decrease in cervical and uterine cancer deaths in the last 40 years. It is considered a reliable technique and is still expanding by being applied to other organs and systems and in the use of fine needle aspiration.

Cell Biology↗

The implantable cardioverter-defibrillator: clinical results.

To evaluate the effectiveness of the automatic implantable cardioverter-defibrillator (AICD), a 7-year experience, from 1983-1990, was reviewed. A total of 111 patients received an AICD device. Their ages ranged between 8 and 83 years. Mean age was 63.9 years. There were 91 men and 20 women. Eighty of the patients received the AICD following an out-of-hospital cardiac arrest, while 31 were suffering from intermittent symptomatic ventricular tachycardia. The underlying etiology in 97 patients (87%) was ischemic coronary artery disease, in 11 patients (10%) dilated cardiomyopathy, and in 3 patients (3%) idiopathic ventricular fibrillation. Mean ejection fraction was 33.2%. Implantation of the AICD was performed via a left thoracotomy in 39 patients, median sternotomy in 49 patients and subxiphoid-subcostal approach in 23 patients. In-hospital mortality occurred in one patient who suffered an acute myocardial infarction 4 hours postoperatively. Out-of-hospital mortality was observed in 19 patients. There were two arrhythmic deaths. Follow-up was available for 107 patients. Mean follow-up was 33.1 months. Sixty-six patients (62%) had AICD shocks. The initial appropriate shocks occurred during the first postimplantation year in 91% of the patients. In 53 of the survivors, initial AICD shocks took place within 4.4 +/- 4.7 months from implantation. Thirteen of the 20 patients who died had received appropriate AICD shocks. In these patients, the time between implantation and first shock was 2.7 +/- 3.6 months whereas the time between implantation and death was 11.3 +/- 10.3 months (NS). We conclude that the AICD is effective in converting ventricular tachyarrhythmias and prolongs survival.

Electric Countershock↗

The kinetics and quantitation of platelet deposition on control (CPC) and heparin-bonded polyurethane angio-catheter (HBPC) with indium-111 labeled platelets in a dog model.

The dynamics of platelet deposition on CPC and HBPC was evaluated with In-111 labeled platelets (In-PLT) with a computerized gamma camera (CGC). Ten non-heparinized dogs (18-25 kg) were catheterized in both femoral arteries with 10 cm of CPC and HBPC (5 Fr., Cordis, Inc.) 24 hours post-injection of 300-420 microcuries of In-PLT, and imaged for 3 hours with gamma camera. The regional platelet deposition on three segments of catheters and puncture site was determined. The catheters were harvested and radioactivity on the catheter segments (proximal: PROX, middle: MID, distal: DIST and puncture site: PS) of both was determined. From the platelet count in blood, radioactivity in blood and segments of catheters, adjacent artery and area of artery and catheter, the platelet-density [X10(3)] (mean +/- S.D.) on catheter and artery were calculated and tabulated: (table; see text) The large standard deviation of retained platelets is due to embolization. The platelet-density and regional counts on catheter segments were lower in the HBPC than CPC. The rate of platelet-deposition was lower in the HBPC than CPC. Most of the thrombi were lost during pullout of the catheter. Both in vivo (dynamic) and in vitro studies were necessary for evaluation of CPC thrombogenicity.

Animals↗

Clinical experience with subxiphoid drainage of pericardial effusions.

To assess the effectiveness of subxiphoid pericardial tube drainage for treatment of pericardial effusion, we reviewed 41 consecutive patients who underwent this procedure during a 14-year period. The patients ranged in age from 7 months to 75 years. All were symptomatic preoperatively. The diagnosis of pericardial effusion was confirmed by echocardiogram in all but 2 patients. Eight patients had acute pericardial tamponade. Subxiphoid pericardial drainage was performed under general (n = 35) or local anesthesia (n = 6). A portion of the anterior pericardium was excised in each patient. There were no perioperative deaths. Thirty-day mortality was 19.5%; there were five late deaths. All deaths were unrelated to pericardial effusion or to the operation. One patient had recurrent effusion requiring pericardiocentesis on the 21st postoperative day. He died five days later of extensive lymphoma. Twenty-eight patients were followed from 1 month to 10 years; mean follow-up was 31.5 months. None developed recurrent effusion or pericardial constriction. We conclude that subxiphoid pericardial drainage is effective for treatment of pericardial effusion.

Adolescent↗

Hemodynamic effects of radical left ventricular scar resection in patients with and without congestive heart failure.

To evaluate the hemodynamic changes that occur following radical left ventricular scar resection we studied 40 patients (mean age, 59.2 years; 36 males) with complete hemodynamic evaluation preoperatively (preop) and 5 to 12 days postoperatively (postop). Severe congestive heart failure (CHF) was present in 15 patients, ventricular arrhythmias in 19, and angina in 19 patients preop. The operation consisted of extensive scar resection with complete myocardial revascularization (average 2.4 grafts per patient). Ten patients required intraaortic balloon pump assist for up to 8 days postop. Postoperative left ventricular ejection fraction (EF) was estimated with multiple gated acquisition scanning. A significant rise in heart rate was observed in the whole group of patients postop (P = 0.000). In the group of patients with CHF preop the EF was increased from 25.1 +/- 8.4% (mean +/- SD) preop to 30.9 +/- 11.2% postop (P = 0.003), the cardiac index was increased from 2.2 +/- 0.5 liters/min/m2 preop to 2.7 +/- 0.5 liters/min/m2 postop (P = 0.02), and the pulmonary artery wedge pressure was decreased from 22.0 +/- 7.7 mm Hg preop to 15.5 +/- 4.3 mm Hg postop (P = 0.005). In the patients without active CHF preop no improvement in the above hemodynamics was noted. In conclusion, radical left ventricular scar resection significantly increased EF and CI and decreased PAW in patients with preop CHF, whereas in the absence of CHF this procedure resulted in minimal hemodynamic changes.

Adult↗

Comparison of long-term results of Carpentier-Edwards and Hancock bioprosthetic valves.

The long-term survival following valve replacement with Carpentier-Edwards or Hancock bioprostheses was compared between the two valve models and between the two groups totaling 407 patients who were discharged after valve replacement beginning in 1974. The two groups of patients were treated in a nonrandomized fashion. The actuarial survival for 299 patients with Carpentier-Edwards valves was 94 +/- 1.5% (+/- standard error) and 93 +/- 1.7% after 5 and 8 years of follow-up, respectively. Comparable figures for 108 patients undergoing valve replacement with Hancock valves were 89 +/- 3.0% and 83 +/- 3.7%, respectively (p = not significant [NS]). The probability of freedom from death and valve removal after 5 and 8 years of follow-up was 91 +/- 1.8% and 79 +/- 4.6%, respectively, with the Carpentier-Edwards valve and 84 +/- 3.5% and 75 +/- 4.3%, respectively, with the Hancock valve (p = NS). An accelerated rate of attrition for both valves was observed in the mitral position. There were no significant differences in actuarial survival between the two valves in the mitral or the aortic position or in the incidence of major valve-related complications.

Adolescent↗

The automatic implantable cardioverter-defibrillator: results, observations, and comments.

The automatic implantable cardioverter-defibrillator (AICD) is a device of proven efficacy in life-threatening ventricular tachycardia and fibrillation. Initial experience with the AICD at the University of Miami consists of 21 patients with recurrent ventricular dysrhythmias for a total follow-up of 3-35 months (mean 19). There were two deaths in the series, one nonarrhythmic and one arrhythmic, at the fifth and tenth postoperative months respectively. There were five complications requiring reoperation in three patients. Pacemakers were required in four patients with the AICD and resulted in interesting observations. Our data concur with previously published reports of improved survival in selected patients.

Adult↗

Surgical management of post-myocardial infarction ventricular tachyarrhythmia by myocardial debulking, septal isolation, and myocardial revascularization.

Sustained ventricular tachycardia or ventricular fibrillation, associated with severely depressed left ventricular function after myocardial infarction, carries a poor prognosis. We have used an extensive surgical procedure in 18 patients (15 men and three women) with a mean age of 63 years who had more than three episodes of recurrent, hemodynamically significant ventricular tachycardia or fibrillation and congestive heart failure. The operation consisted of complete myocardial revascularization and myocardial debulking by extensive infarctectomy with unguided endocardial resection and septal isolation with support of the necrotic wall with a Teflon patch. Implantable defibrillator patches were placed in eight patients. Blood cardioplegia and intra-aortic balloon assist (12 patients) were used for perioperative myocardial preservation. Postoperative studies demonstrated a significant increase in ejection fraction (n = 16) and a decline in pulmonary wedge pressure. Hospital mortality was 16% (three patients). Two deaths were due to congestive heart failure and one to arrhythmia. During postoperative electrophysiologic studies, ventricular tachycardia was not inducible in six of eight patients (75%). During a mean follow-up of 24 months, 11 of 15 patients who survived operation are alive and are in New York Heart Association Class I or II. Three of four late deaths were due to congestive heart failure and drug toxicity and one was arrhythmia related. This procedure is effective for preventing recurrent ventricular tachycardia or fibrillation in a majority of patients who cannot have intraoperative mapping.

Aged↗

Changing trends in the surgical treatment of coarctation of the aorta.

From 1974 through 1983, 107 patients 4 days to 27 years old underwent 115 operations for treatment of coarctation of the aorta. Thirty-two patients were infants (1 year old or younger), and 28 of them were newborns. All newborns were seen with congestive heart failure. Seventy-one patients were seen with hypertension. Associated anomalies were present in 72 patients (67%). Resection was performed in 48 patients, patch aortoplasty in 16, bypass of the coarcted segment in 15, and left subclavian artery flap angioplasty (LSAFA) in 36. Ligation of a patent ductus arteriosus was simultaneously performed in 28 patients and pulmonary artery banding, in 4. Follow-up was 6 months to 9.2 years. There was a significant difference in aortic cross-clamp time between 26 patients who had resection (37.9 +/- 12.9 minutes) (mean +/- standard deviation) and 32 patients who had LSAFA (22.9 +/- 7.7 minutes) (p less than 0.05). Six patients died within thirty days after operation; 5 of them had resection, and 1 had bypass. Major postoperative complications included bleeding requiring exploration in 3 patients (2 after resection and 1 after LSAFA) and paraplegia in 1 patient after reoperation (resection) for recurrent coarctation 3 years after patch aortoplasty. Paradoxical hypertension was observed in 13 patients, and sustained systemic postoperative hypertension developed in 11 after effective repair of coarctation. There was no significant difference in early postoperative arm-leg pressure gradients between the types of operation or the various age groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta↗

Comparison of effectiveness and safety of operations on the pericardium.

A ten-year experience with operations on the pericardium in 71 consecutive patients was reviewed. The patients ranged in age from nine months to 75 years old. Fifty-three patients were operated upon for pericardial effusion and 14 for pericardial constriction. Sixty-seven patients had pericarditis: 21 of them underwent subxiphoid tube drainage; ten, limited pericardiectomy; and the remaining 36, extensive pericardiectomy. There were two trauma victims who underwent diagnostic pericardiotomy. Two patients underwent excision of pericardial cysts. There was one operative death during extensive pericardiectomy for constrictive tuberculous pericarditis. Thirty-day mortality was three of 21 patients after subxiphoid tube drainage, three of ten after limited pericardiectomy and five of 36 after extensive pericardiectomy. Postoperative complications consisted of pulmonary problems in four patients (two after pericardiectomy and two after extensive pericardiectomy), cardiac arrhythmia in one patient after tube drainage and postpericardiotomy syndrome in one patient after extensive pericardiectomy. Mean follow-up was 3.2 years. Recurrent pericardial effusion occurred in two patients; one had limited pericardiectomy but did not require reoperation and one had diagnostic pericardiotomy without drainage. Six patients with persistent postirradiation pericardial effusion were treated effectively with extensive pericardiotomy. Our experience indicates that subxiphoid tube drainage is effective for the treatment of pericardial effusion and safer than limited pericardiectomy, while extensive pericardiectomy is the operation of choice for pericardial constriction and radiation-related pericardial effusion.

Adolescent↗