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Biomedical subjects

R Mair

Publications and source records attributed to R Mair.

At least 19 recordsLinked to original sources
PubMed2006

Activated thrombelastogram in neonates and infants with complex congenital heart disease in comparison with healthy children.

BACKGROUND: The goal of the study was to determine activated thrombelastographic (TEG(R)) parameters with the rotational TEG(R) (ROTEG or ROTEM) device (Pentapharm GmbH, Munich, Germany) in neonates and infants <1 yr with complex congenital heart disease (CCHD) and to compare them with those of healthy children. METHODS: A total of 59 children were included: Group I (Gr I) 24 children, ASA I, scheduled for minor surgery; and Group II (Gr II) 35 children with CCHD, ASA III-IV, scheduled for cardiac surgery. Each group was subdivided into four age groups. Blood samples were obtained before the surgical procedure. RESULTS: Statistically significant differences (two-way anova analysis) between Gr I and Gr II [mean (SD); P-value] were found in INTEG-CT [Gr I 175(19), Gr II 271(162); P=0.049], EXTEG-MCF [Gr I 63(8), Gr II 56(8); P=0.013], EXTEG-MCE [Gr I 186(65), Gr II 137(41); P=0.003], FIBTEG-MCF [Gr I 24(7), Gr II 19(5); P=0.012], FIBTEG-MCE [Gr I 32(13), Gr II 24(8); P=0.012] and EXTEG-MCE-FIBTEG-MCE [Gr I 155(55), Gr II 113(37); P=0.003]. Clotting time via contact activation was prolonged in Gr II and varied widely, mainly in the age group 0-1 month and to a lesser extent in 1-3 months, and maximum clot firmness was reduced in the same age groups. In comparison with Gr II, the healthy children showed relatively homogenous TEG values with a tendency to hypercoagulability; the maximum was found in age group 1-3 months, decreasing towards adult values in the course of the first year of life. CONCLUSIONS: These preliminary TEG results indicate that the coagulation-fibrinolytic system in CCHD patients <1 yr is functionally intact and balanced but at a lower level than in healthy children. This could be interpreted as a reduction in the haemostatic potential with less reserve.

Aging↗
PubMed2005

Monitoring of selective antegrade cerebral perfusion using near infrared spectroscopy in neonatal aortic arch surgery.

BACKGROUND AND OBJECTIVE: To prevent neurological complications, low-flow antegrade cerebral perfusion (ACP) is used during repair of complex congenital heart defects. To overcome technical problems, continuous monitoring of cerebral blood flow and oxygenation is mandatory. The aim of the study was to evaluate the effect of different ACP flow rates on cerebral oxygen saturation obtained by near infrared spectroscopy. METHODS: Ten consecutive neonates undergoing Norwood stage I were included. In addition to near infrared spectroscopy (Invos 5100; Somanetics Corp., USA) on both hemispheres, mean arterial pressure and transcranial Doppler flow velocity were measured continuously and arterial and jugular venous oxygen saturation intermittently. Cerebral oxygen extraction ratio was calculated. Measurement points were obtained after starting bypass, during ACP with flow rates of 30, 20 and 10 mL kg(-1) min(-1) and immediately after ACP. ANOVA and Tukey-Kramer multiple comparison test were used for statistics. RESULTS: The near infrared spectroscopy signal could be obtained in all children at all measurement points, whereas transcranial Doppler failed in 1 neonate at a flow rate of 30 mL kg(-1)min(-1), in 3 neonates at 20 mL kg(-1) min(-1) and in 4 neonates at 10 mL kg(-1)min(-1). With the reduction of flow there was a significant decrease of cerebral oxygen saturation on both hemispheres (right: 78+/-8 to 72+/-9 and 66+/-8, P < 0.001; left: 71+/-7 to 65+/-7 and 60+/-7, P < 0.001), of jugular venous oxygen saturation (94+/-6 to 89+/-13 and 83+/-15, P < 0.001) and a significant increase in oxygen extraction ratio (9.1+/-8 to 14.8+/-14 and 21+/-16, P < 0.001) respectively, for 30, 20, 10 mL kg(-1)min(-1). CONCLUSION: Near infrared spectroscopy reliably detects flow alterations during ACP with profound hypothermia.

Anesthesia, General↗
PubMed2003

Invasive intrauterine treatment of pulmonary atresia/intact ventricular septum with heart failure.

The mortality and morbidity of children with pulmonary atresia/intact ventricular septum (PA/IVS) are linked to the degree of right ventricular (RV) hypoplasia. Opening up the pulmonary valve (PV) in fetal life could result in improved growth of the RV making it amenable to biventricular repair postnatally. Successful valvulotomy of the PV was performed in a fetus with heart failure at 28 weeks. Following the procedure there was significant growth of the tricuspid valve and RV. The neonate was delivered at 38 weeks with a RV suitable for biventricular repair. In utero pulmonary valvulotomy is feasible and may change the natural history of the condition in affected fetuses with PA/IVS.

Adult↗
PubMed2000

Assessment of hearing in persons with learning disabilities: the Phoenix NHS Trust, January 1997 to September 1998.

People with learning disabilities are at increased risk of impaired hearing. The aims of this study were to assess the prevalence of hearing impairment and ear disease in people attending the specialist Otolaryngology/Hearing Therapy clinic at the Phoenix NHS Trust, Bristol. The present and future process of such a service was explored. Data were obtained from the referral form and notes made by the consultant otolaryngologist. In 20 months, there were 226 consultations, 188 of which were new referrals. The majority of patients had verbal communication to some extent. Suspected infection/inflammation and unobtainable/abnormal tympanograms, each accounted for 43 per cent of reasons for referral. Twenty per cent of patients were normal otologically. Eighteen per cent were provided with hearing aids and nine per cent required surgery. Ten patients underwent brainstem evoked response testing, half of whom had aidable hearing. Our results are comparable to published data of similar units. It is recommended that combined otolaryngology/specialist hearing therapy services are continued and further developed.

Adult↗
PubMed1999

Aortic valve replacement: is the stentless xenograft an alternative to the homograft? Midterm results.

BACKGROUND: This study was performed to assess the midterm clinical results after aortic valve replacement (AVR) with stentless xenograft (SX) compared with cryopreserved aortic or pulmonary homografts (HX). METHODS: In 139 patients (<60 years) undergoing elective AVR, 59 HX and 80 SX were inserted. All patients were followed clinically and by color flow Doppler echocardiography for 45+/-12 months (range 31-58 months). RESULTS: There were 5 in-hospital deaths (3.5%): 4 HX and 1 SX (p = NS). The mean gradient was 6+/-2 mm Hg in HX versus 13+/-6 mm Hg in SX (p<0.001) and remained unchanged during follow-up. Actuarial survival (HX 77%, SX 80%), freedom from endocarditis (HX 91%, SX 99%), freedom from thromboembolic events (HX 98%, SX 90%), and freedom from reoperation (HX 98%, SX 100%) were comparable between groups after 58 months. CONCLUSIONS: Despite slightly higher transvalvular gradients, the stentless aortic valve achieved excellent midterm results, when compared with homografts.

Actuarial Analysis↗
PubMed1999

Midterm results after aortic valve replacement with the autologous tissue cardiac valve.

OBJECTIVE: To assess midterm results after aortic valve replacement (AVR) with an autologous tissue cardiac valve (ATCV). This new technique was developed to construct a tissue prosthesis for AVR using the patients pericardium, harvested at the time of operation with negligible effect on operating time. METHODS: Briefly, glutaraldehyde tanned pericardium is mounted on a stent requiring no suturing. Between March 1994 and December 1996, 87 patients, 44/43 M/F and aged 70 +/- 6 years had AVR for aortic stenosis (80%), aortic insufficiency (6%) and combined lesions (14%), one patient suffered from endocarditis. Additional coronary artery bypass was done in 25%, aortic root enlargement in 7%. Aortic cross clamp and cardiopulmonary bypass times were 69 +/- 21 and 93 +/- 29 min. All patients were followed by clinical examination and color flow Doppler echocardiography in 3-12 months interval. Follow up was 99% complete. RESULTS: There were five perioperative deaths (6%), none of them valve related. Eighty-one patients were followed up to a period of 52 months (mean interval 37.5 +/- 1.3 months), one patient was lost for follow up. Overall survival was 86, 81, 79 and 71% at 12, 24, 36 and 48 months, respectively. There were 14 late deaths with eight (10%) valve related (four cerebral deaths, four sudden deaths). Sixteen patients (20%) had to be re-operated due to severe valve incompetence. Freedom from reoperation was 98, 97, 90 and 63% at 12, 24, 36, and 48 months, respectively. Valve incompetence occurred suddenly, without previous signs in the follow-up examinations. Selection and preparation of the pericardium, the way of fixation of the tissue--brief immersion in glutaraldehyde--and engineering problems might be responsible for this disastrous outcome. CONCLUSION: Due to these results we must state, that the ATCV did not fulfill our expectations and presently we can not recommend it as an aortic valve substitute.

Aged↗
PubMed1998

Aortic homografts versus mechanical valves in aortic valve replacement in young patients: a retrospective study.

BACKGROUND: Whether aortic homografts (AH) or mechanical devices (MD) are the valves of choice for aortic valve replacement in young patients (age 20 to 50 years) is unclear. Hence, we examined all aortic valve replacements performed with AH and MD in a retrospective study. METHODS: Between 1988 and 1995, 45 patients (mean age, 38.6+/-8.5 years) underwent aortic valve replacement with an AH and 40 patients (mean age, 42.0+/-7.2 years) with an MD. Patients' demographic data were comparable in all respects, except acute endocarditis, which was an absolute indication for the use of an AH. RESULTS: The mean follow-up time was 51.7+/-22.6 months for AH versus 44.6+/-26.9 months for MD (not significant). There were significant differences in postoperative outcome among the two groups (p < or = 0.05): perioperative death (4 versus 0 for AH and MD, respectively); reoperation (8 for AH versus 0 for MD); and endocarditis (5 versus 0 for AH and MD). There were higher incidences of embolism (2 versus 0) and hemorrhage (2 versus 0) in MD compared with AH. Only late death was comparable among the two groups with 5 patients in each group. CONCLUSIONS: The mechanical valves in our midterm follow-up are superior to homografts. However, embolic and hemorrhagic complications in MD are continuously impending and cumulative during a long-term follow-up. The surprisingly high rate of endocarditis in the AH group is only partly caused by the indication: 2 cases were recurrent, but there were also 2 new onsets of endocarditis. In 4 cases structural deterioration was responsible for reoperation. Aortic valve replacement with aortic homografts showed a rather unfavorable midterm outcome in this selected group of young patients. A surprisingly high rate of graft endocarditis and structural deterioration led to subsequent reoperations. Although our results with mechanical valves are satisfying, embolism and hemorrhage are impending risk factors for many years to come in these young patients.

Adult↗
PubMed1998

Bilateral nephrectomy: the best, but often overlooked, treatment for refractory hypertension in hemodialysis patients.

Bilateral nephrectomy for treatment of refractory hypertension in chronic hemodialyzed patients has been infrequently carried out. We analyzed the benefits of this operation on blood pressure, clinical state, drug treatment, and quality of life. In 10 hemodialyzed patients with refractory hypertension, systolic (SBP) and diastolic (DBP) blood pressure were measured 1 month before nephrectomy bilateral and 3, 6, 9, and 12 months after. In addition, the use of antihypertensive drugs before and after surgery was evaluated. Four patients had SBP and DBP values characteristic of malignant hypertension. In all 10 patients hypertension responded neither to reduction of plasma volume by ultrafiltration nor to multiple antihypertensive drug therapy. Hypertensive crises were associated with cerebral hemorrhage in two patients, severe encephalopathy with persistent neural dysfunction in one patient, and encephalopathy and diplopia in another. Three months after bilateral nephrectomy blood pressure decreased significantly (P < .005) and was normal in nine patients. In one noncompliant patient with intradialytic body weight increases of nearly 10%, blood pressure was still elevated. Malignant or drug-resistant hypertension with hypertensive crises is an indication for bilateral nephrectomy. The clinical state and quality of life improved in all patients in the present study and antihypertensive treatment is no longer necessary.

Adult↗
PubMed1997

The pulmonary homograft as aortic valve substitute: 7 years' follow up.

OBJECTIVE: The advantages of the aortic valve homograft high resistance to infective endocarditis, low risk of thromboembolism, low gradient and excellent long term results are well known. Trying to extend these advantages to a greater number of patients, we used pulmonary homografts as aortic valve substitute, based on the experimental evidence, that they can withstand the higher stress in systemic circulation. METHODS: From September 1988 to August 1994 175 patients (103 men, 72 women, mean age 61.75 +/- 12.92 years) underwent aortic valve replacement with a cryopreserved pulmonary homograft. All valves were taken from our own homograft bank. They were inserted freehand intraaortically, 162 in subcoronary position, 13 as intraaortic cylinder. All patients were followed clinically and by colorflow Doppler echocardiography in 3-12 month intervals. RESULTS: Patients, 8, died perioperatively (4.57%). None of the deaths was valve related. Patients, 2, had to be reoperated during the perioperative period due to severe valvular incompetence 165 patients were followed up to a period of 7.5 years (mean interval 3.83 +/- 1.45 years). Patients, 30, died, 13 deaths (7.42%) must be regarded as valve related. Patients, 22, (12.52%) had to be reoperated due to severe graft incompetence. Patients, 9 (5.14%), acquired prosthetic endocarditis. CONCLUSION: Due to our results, high rate of valve related deaths, high rate of graft failure and high rate of prosthetic endocarditis, we must state that the pulmonary homograft did not fulfil our expectations and presently we can not recommend it as an aortic valve substitute.

Aortic Valve↗
PubMed1996

Autologous tissue cardiac valve for aortic valve replacement: technical aspects and early results.

BACKGROUND: The known complications of heterograft bioprostheses and homograft valves have renewed the interest in the use of autologous material. A new technique to construct a tissue prosthesis for aortic valve replacement using the patient's pericardium harvested at the time of operation was developed. The glutaraldehyde-tanned pericardium is mounted on a stent requiring no suturing. Intraoperative testing assures adequate valve function. METHODS: The autologous tissue cardiac valve was implanted in 50 patients in the aortic position between March 1994 and May 1995. Echocardiograms were performed in all patients before hospital discharge, at 3 months (41 patients), and at the end of first postoperative year (12 patients). The mean age was 69.8 +/- 5 years (range, 58 to 82 years). Eighty-four percent of patients presented with aortic stenosis and 16% had a combined lesion. Additional cardiac procedures were performed in 21 patients. RESULTS: Aortic cross-clamp time was 72 +/- 19 minutes, and bypass time was 97 +/- 28 minutes. There were three in-hospital deaths, and 2 patients died within the first postoperative year. Predischarge echocardiography demonstrated excellent hemodynamics, with a mean gradient of 20 +/- 8 mm Hg and no or trivial aortic insufficiency in 45 patients. One patient had moderate aortic insufficiency. At first follow-up 36 patients (90%) were in New York Heart Association class I and 4 patients were in class II. Echocardiography showed no evidence of valve failure or degeneration (mean gradient, 17 +/- 5mm Hg; aortic insufficiency = grade 0 [trivial] in 35 patients, grade II in 3 patients, and grade III in 1 patient). Similarly, no degeneration or valve failure with increasing aortic insufficiency was seen in the patients studied at the end of the first postoperative year. CONCLUSIONS: These results demonstrate that an autologous tissue cardiac valve can be manufactured in the operating room without significant additional operating time. Intraoperative testing minimizes the risk of primary failure with aortic insufficiency. Short-term results are encouraging with good hemodynamic performance of the valve and no signs of degeneration. However, long-term durability needs to be demonstrated.

Aged↗
PubMed1995

Aortic valve replacement: is the stentless xenograft an alternative to the homograft? Early results of a randomized study.

From November 1992 to October 1993 we randomized 101 patients over 60 years of age undergoing elective aortic valve replacement, with or without concomitant coronary artery bypass grafting, to receive either a cryopreserved aortic or pulmonary homograft (n = 38) or a stentless porcine aortic valve xenograft (Edwards Prima 2500) (n = 63). The majority of all valves (92%) were inserted freehand in the subcoronary position. Six homografts (16%) were implanted as a free-root replacement and two xenografts (3%) were used as a mini root. There were four in-hospital deaths (4%), three in the homograft group and one in the xenograft group (homograft, 7.9% versus xenograft, 1.6%; p = not significant). Forty-one patients were followed at 3- to 6-month intervals for 9 +/- 2 months (3 to 14 months) and valve pathology was assessed routinely by means of color flow Doppler echocardiography. Two patients in the homograft group developed new aortic insufficiency grade II; all others remained with trivial or no valve incompetence. The mean gradient remained unchanged to immediate postoperative measurements (homograft, 5 +/- 1 mm Hg versus xenograft, 11 +/- 4 mm Hg; p < 0.001). Despite a slightly higher transvalvular gradient, xenografts achieved excellent initial results when compared to homografts. Ease of implantation and freedom from thromboembolism indicate that xenografts can be an acceptable alternative to homografts, particularly in older patients with small aortic annuli. Long-term studies assessing the durability of the xenograft are necessary for final evaluation.

Aged↗
PubMed1995

Aortic valve replacement with cryopreserved pulmonary allografts: five years' follow-up.

Excellent clinical results with pulmonary autografts and experimental evidence that pulmonary valves can withstand the higher stress in the systemic circulation led us to use the cryopreserved pulmonary allograft for aortic valve replacement. From September 1988 until March 1993, 126 consecutive patients (61 +/- 10 years; 74 men and 52 women) underwent aortic valve replacement with a cryopreserved pulmonary allograft. All allografts were inserted freehand in the subcoronary position. There were four in-hospital deaths (3.2%), and 1 patient had severe valvular incompetence immediately postoperatively, requiring reoperation after 4 weeks. One hundred twenty-one patients were followed up in 3- to 6-month intervals for 25.3 +/- 16.3 months (range, 6 to 66 months), and valve performance was assessed routinely by means of color-flow Doppler echocardiography. Nine patients (7.1%) died during follow-up. Two patients died of multiple septic emboli during bacterial endocarditis, and 1 patient died of a massive stroke. The other 6 patients died of myocardial infarction (4), respiratory insufficiency due to chronic obstructive lung disease (1), and carcinoma (1). Ninety-four patients (78%) had absent or trivial aortic valve regurgitation. Valvular incompetence class II was present in 3 patients (2.5%), whereas 5 others (4%) demonstrated class II to III. Severe aortic regurgitation (class III or IV) could be detected in 10 patients (8.3%). All underwent reoperation and replacement of the valve with a prosthetic device. Bacterial endocarditis caused graft incompetence in 3 patients, valve degeneration was detected in another 3, and technical mistakes at valve implantation caused valve failure in the other 4.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1995

[Heart surgery in the elderly].

The number of octogenarian patients undergoing an open heart procedure in our unit is the fastest increasing group of patients. Between June 1985 and July 1994 112 octogenarians (mean age 81.7 years, 60 males, 52 females) underwent cardiac operations. The postoperative course was uneventful in 90 patients (80.4%). The perioperative mortality rate was 8.9% (10 patients). Mortality was lowest in the group receiving aortic valve replacement, with one death out of 30 patients (3.3%). The cause of death was left- or biventricular heart failure in more than half of the fatalities. Postoperative complications included: AV-block III (n = 1), postoperative bleeding (n = 2), unstable sternum (n = 3), acute cholecystitis (n = 1), low cardiac output syndrome (n = 1), stroke (n = 1), pneumothorax (n = 2) and urinary tract infections (n = 1). We consider open heart procedures in octogenarians, despite a mortality rate of 8.9%, as justified. According to the severity and course of clinical symptoms and the type of surgery required, selection of patients for operation should be decided on at an early stage of the disease. Not only life expectancy increases, but there is also a significant increase in life quality for these patients.

Aged↗
PubMed1994

[Use of autologous femoral vein in superior vena cava thrombosis. Case report and review of the literature].

We report on a 52-year old male patient who underwent implantation of an insulin pump because he had diabetes and in whom superior vena cava syndrome developed as a long-term complication. After unsuccessful lysis therapy superficial femoral vein was implanted to form a bypass from the internal jugular vein to the right atrium. The postoperative course was uneventful from the aspects of both the bypass and the leg after explantation of the superficial femoral vein. The bypass is still patent 7 months after the operation, and the patient has no symptoms. Autogenous superficial femoral vein can be used successfully in the reconstruction of large venous vessels. It should be the graft of choice for young patients with benign diseases. We compare our result and those obtained with different substitutes described in the literature that have been used for reconstruction in superior vena cava syndrome.

Femoral Vein↗
PubMed1994

Mycotic aneurysms of the thoracic aorta.

Between February 1982 and December 1992 we operated on five patients (three men, two women; aged 40 to 70 years) with mycotic aneurysms of the thoracic aorta. One patient had an aneurysm of the ascending aorta, once the aortic arch and in three cases the descending thoracic aorta were involved. In four of the five patients, excision of the aneurysm and in situ reconstruction of the aorta with a Dacron graft was performed, one patient required a Dacron graft repair and aortic valve replacement. We employed deep hypothermia with circulatory arrest (2), extracorporeal circulation (1), an axillofemoral shunt (1) and a centrifugal pump (1) for cerebral and spinal cord protection. One patient died 4 months postoperatively, the other four patients were without recurrent graft infection and are free of symptoms between 20 months and 5 years postoperatively.

Adult↗
PubMed1994

The octogenarians--a new challenge in cardiac surgery?

The per- and early postoperative outcomes of 75 consecutive octogenarians (38 male, 37 female, mean age 81.7 years) who underwent open heart surgery were analysed to identify independent variables of risk factors influencing morbidity and mortality. There were 48 coronary bypasses. 20 valve replacements, and 7 combined procedures. Multivariate analysis revealed that functional class (New York Heart Association), operative procedure, aortic cross clamp time, total bypass time, and age are independent predictors for morbidity and mortality (p < 0.05). There were 6 postoperative deaths (8%). Postoperative complications included haemorrhage (2), stroke (1), unstable sternum (2), acute cholecystitis (1), pneumothorax (2), and urinary tract infection. It is concluded that octogenarians may benefit from open heart surgery at an acceptable risk.

Aged↗
PubMed1994

Coronary disease and tracheal stenosis with tracheo-oesophageal fistula: a combined surgical procedure.

A patient with coronary disease class III of the New York Heart Association and tracheal stenosis with a tracheo-oesophageal fistula, which developed after long-term intubation, is described. As both conditions were symptomatic, an aortocoronary double bypass was combined with resection of the trachea and closure of the fistula. Postoperative recovery was uneventful and the patient is symptom-free after 3 years.

Adult↗