WITHDRAWN: Higher coracoacromial ligament thickness, critical shoulder angle and acromion index are associated with rotator cuff tears in patients who undergo arthroscopic rotator cuff repair.

PURPOSE: To evaluate the effect of several shoulder anatomical parameters in the development of rotator cuff tear (RCT). METHODS: Between 2014 and 2018, all consecutive patients who underwent arthroscopic rotator cuff repair due to full-thickness rotator cuff tear with a minimum 2-year follow-up were identified. Inclusion criteria were (1) age>18 years, (2) patients with degenerative RCT, (3) full-thickness RCTs, (4) patients underwent arthroscopic RCR due to unresponsive conservative treatment, (5) minimum 2-year follow-up period. Exclusion criteria were traumatic RCT, history of previous shoulder surgery, shoulder deformity, neurologic or neuromuscular dysfunction, glenohumeral and/or acromioclavicular joint arthritis, cuff-tear arthropathy, history of fracture around shoulder and inadequate or low-quality magnetic resonance images (MRI). Acromion index (AI), Critical shoulder angle (CSA), Coracoacromial ligament (CAL) thickness, Subacromial space (SS) width, Acromiohumeral distance (AHD), CAL/SS ratio, Lateral acromial angle (LAA) and glenoid version angle (GVA) parameters were measured on MRI. Intra- and interobserver reliability were measured. Regression analysis was used to evaluate the association between anatomical parameters and RCT development. Receiver operating curves (ROC) were created for independent risk factors. The correlation between measurement parameters were evaluated. RESULTS: There were 1029 patients met the inclusion criteria. After exclusions, 437 patients were included. Age- and sex matched 437 patients without any shoulder pathologies were selected as control group. There was almost perfect intra- (ICC>0.85) and interobserver (ICC> 0.81) reliability regarding all measurement parameters. There was significant difference between RCT group and control group regarding AI (0.67±0.07 vs. 0.61±0.08, p<0.001), CSA (33.58±3.93 vs. 31.50±4.01, p<0.001), CAL thickness (1.81±0.64 vs. 1.53±0.50, p<0.001), CAL/SS ratio (0.29±0.14 vs. 0.23±0.10, p<0.001) and GVA (-16.69±6.69 vs. -15.37±5.95, p=0.002) parameters. AI (OR: 1.998, P<0.001), CAL thickness (OR: 2.801, p<0.000) and CSA (OR: 3.055, p<0.001) were found to be independently associated with the increased risk of RCT development. Area under curve (AUC) of the AI, CSA, and CAL thickness were 71.4%, 71.3%, and 70.2%, respectively. Cut-off values for AI, CSA, and CAL thickness were 0.62, 36.4° and 1.47 mm, respectively. There was significantly positive strong correlation between AI and CSA (p<0.001, r=0.814). CONCLUSION: Higher AI, CSA and CAL thickness independently associated with full-thickness RCT development. In clinical practice, these parameters may be useful in the prediction of rotator cuff rupture.

The critical shoulder angle, the acromial index, the glenoid version angle and the acromial angulation are associated with rotator cuff tears.

PURPOSE: To compare the critical shoulder angle (CSA), acromion index (AI), acromion angulation (AA) and glenoid version angle (GVA) between patients with full-thickness rotator cuff tears (RCTs) and patients with intact rotator cuffs. METHODS: Between 2014 and 2018, the CSA, AI, AA and GVA were measured in consecutively included patients aged > 40 years who underwent shoulder arthroscopy for full-thickness RCTs. A total of 437 patients with RCTs and a mean age of 51.2 years (± 5.8) were included, 35.7% of whom were male. In the control group, there were n = 433 patients (36.3% male) with an intact rotator cuff, and the mean age was 50.7 years (± 5.3). RESULTS: The mean AI for the RCT group was 0.7 ± 0.1, which was significantly higher than the mean AI for the control group (0.6 ± 0.1, p < 0.001). The mean CSA for the RCT group was 33.6° ± 3.9°, which was significantly higher than the mean CSA for the control group (31.5° ± 4°, p < 0.001). The mean AA for the RCT group was 13.9° ± 9°, which was significantly higher than the mean AA for the control group (12.4 ± 8.6, p = 0.012). The mean GVA for the RCT group was - 3.5° ± 4.6° and significantly retroverted compared with the mean GVA for the control group (- 2.2° ± 4.6°, p < 0.001). The cutoff values determined by the ROC curve analyses were as follows: 0.6 for AI, 31.4° for CSA, 9.6° for AA and - 2.6° for GVA. CONCLUSION: The CSA, AI, GVA and AA values measured by MRI were determined to be significantly related to full-thickness rotator cuff ruptures. The AI, CSA, AA and GVA may be considered risk factors for degenerative rotator cuff tears. Assessing the CSA, AI, GVA and AA can be helpful for diagnostic evaluation of patients with full-thickness RCTs. LEVEL OF EVIDENCE: III.

Changes in Hip, Knee, and Ankle Coronal Alignments After Total Hip Arthroplasty With Transverse Femoral Shortening Osteotomy for Unilateral Crowe Type IV Developmental Dysplasia of the Hip.

BACKGROUND: To investigate changes in lower extremity coronal alignment in patients with unilateral Crowe type IV developmental dysplasia of the hip who underwent total hip arthroplasty with transverse femoral shortening osteotomy. METHODS: We reviewed the preoperative and 1-year postoperative full-length lower extremity radiographs of 25 patients. Femoral offset (FO), mechanical hip-knee-ankle angle, anatomical axis, mechanical axis deviation (MAD), mechanical lateral proximal femoral angle, anatomical medial proximal femoral angle, mechanical lateral distal femoral angle, anatomical lateral distal femoral angle, knee joint line congruency angle, mechanical medial proximal tibial angle, mechanical lateral distal tibial angle, ankle joint line orientation angle, tibial plafond talus angle, extremity length, and pelvic obliquity were measured on both the operative and nonoperative sides. RESULTS: Postoperatively, there were significant changes in FO (P = .001), hip-knee-ankle angle (P = .004), MAD (P = .016), mechanical lateral proximal femoral angle (P = .001), anatomical medial proximal femoral angle (P = .012), mechanical lateral distal femoral angle (P = .043), and ankle joint line orientation angle (P = .012) on the operative side. Only MAD (P = .035) changed significantly on the nonoperative side. CONCLUSION: Modification of FO and reconstruction of hip joint anatomy led to neutralization of knee and ankle valgus alignment. Effects on the nonoperative side were minimal.

Cancer Frequency in Retrosternal Goiter.

Retrosternal goiter prevalence is 5 to 40 per cent according to classifications in goiter series. Goiters with mediastinal extension were reported to be related with higher cancer rates. In our study, we aimed to investigate whether cancer incidence increased in retrosternal goiters compared with the cervical ones. Three hundred and ninety consecutive patients, who had surgery because of retrosternal goiter in Istanbul University Medical Faculty Department of General Surgery between 2005 and 2015 were included in the study (Group 1). Control group included 880 patients who had surgery because of nontoxic multinodular goiter in the same period (Group 2). Preoperative ultrasonography (USG) was performed to each patient. Fine-needle aspiration biopsy was performed in suspicious nodules and results were recorded. Carcinomas in histopathological examination were classified as intrathorasic and extrathorasic. Diagnostic rates of USG results were compared with histopathologic cancer results. Papillary carcinoma was diagnosed in 76 patients with retrosternal goiter (19%) and in 200 patients in the control group (22%). No statistically significant difference was detected between groups regarding the tumor rates (P > 0.05). One hundred and forty-four tumoral foci were detected in 76 patients with papillary carcinoma in retrosternal goiter patients. Three hundred and seventy tumoral foci were detected in 200 patients with papillary carcinoma in the control group. In the retrosternal goiter group, 104 carcinoma lesions of 144 papillary carcinomas were intrathorasic (72%). No statistically significant difference was detected between intrathorasic (2.1 ± 1 cm) and extrathorasic regiones (1.9 ± 0.8 cm) regarding the tumor size P > 0.05. When patients with and without cancer in the retrosternal goiter group were compared regarding familial thyroid cancer history, radiation to the neck, and cervical adenopathy, no statistically significant difference was detected. Cancer incidence of retrosternal goiters was not higher than that of the cervical ones. Yet, cancer foci of retrosternal goiters were commonly located in the intrathorasic area and were not detected with USG. Depending on these findings, we suggest that all retrosternal goiters should be surgically treated.

Intraoperative diagnosis of mitral valve endocarditis secondary to Paenibacillus provencensis.

We report the first case of infective endocarditis caused by Paenibacillus provencensis. A mitral valve vegetation was incidentally discovered by intraoperative transoesophageal echocardiography in a 70-year-old woman undergoing aortic valve replacement. The precise identification of the causative agent was by means of genotypic characterisation with 16S rDNA gene sequencing. The patient was successfully treated with a 6-week course of antibiotics postoperatively, following debridement of the valve vegetation.

Fellow Eye Comparison of Nerve Fiber Regeneration After SMILE and Femtosecond Laser-assisted LASIK: A Confocal Microscopy Study.

PURPOSE: To compare postoperative corneal nerve fiber regeneration after small incision lenticule extraction (SMILE) and femtosecond laser-assisted LASIK (FS-LASIK). METHODS: The medical records of patients who underwent SMILE were retrospectively reviewed. Patients with SMILE in one eye (the SMILE group) and FS-LASIK in the fellow eye (the FS-LASIK group) and who had undergone a confocal microscopy study were retrospectively identified. Subbasal nerve fiber density was measured and compared between the groups preoperatively and at 1 week and 1, 3, and 6 months postoperatively. RESULTS: Thirty eyes of 15 patients were included in the study. Preoperative characteristics of the eyes were similar between the groups. However, there was a statistically significant difference in subbasal nerve fiber density between the groups at 1 month (SMILE group: 1,505 ± 627 µm/mm(2) [range: 625 to 2,540 µm/mm(2)], FS-LASIK group: 1,107 ± 509 µm/mm(2) [range: 595 to 2,313 µm/mm(2)], P = .003) and 3 months (SMILE group: 1,534 ± 503 µm/mm(2) [range: 650 to 2,255 µm/mm(2)], FS-LASIK group: 1,194 ± 485 µm/mm(2) [range: 530 to 1,695 µm/mm(2)], P = .004) postoperatively. No statistically significant difference was detected at 1 week and 6 months postoperatively. CONCLUSION: Eyes treated with SMILE have a higher density of subbasal nerve fibers than eyes treated with FS-LASIK in the early postoperative period (1 week to 3 months) but the two procedures are equivalent by 6 months postoperatively.

Comparison of visual acuity and higher-order aberrations after femtosecond lenticule extraction and small-incision lenticule extraction.

PURPOSE: To compare postoperative visual acuity and higher-order aberrations (HOAs) after femtosecond lenticule extraction (FLEX) and after small-incision lenticule extraction (SMILE). METHODS: Medical records of refractive lenticule extraction patients were retrospectively reviewed. Twenty patients were treated with FLEX. A comparable group of 20 SMILE patients were retrospectively identified. Only one eye of each patient was randomly chosen for the study. Visual acuity, subjective manifest refraction and corneal topography before and 6 months after the surgery were analyzed for both groups. Total HOAs, spherical aberrations, coma and trefoil were calculated from topography data over the 4- and 6-mm-diameter central corneal zone. RESULTS: The mean preoperative SE was -4.03 ± 1.61 in the SMILE group and -4.46 ± 1.61 in the FLEX group. One year after surgery, the mean SE was -0.33 ± 0.25 in the SMILE group and -0.31 ± 0.41 in the FLEX group (p=0.86). In the SMILE group a greater number of eyes were within ±0.50D of the target refraction (95% versus 75%); however, the difference was not statistically significant (p=0.18). Furthermore, 80% of FLEX eyes and 95% of SMILE eyes had an uncorrected distance visual acuity of 20/25 or better (p=0.34). Total HOAs, spherical aberration, coma and trefoil increased postoperatively in both groups. However, there was no statistically significant difference between the groups preoperatively and postoperatively. CONCLUSION: FLEX and SMILE result in comparable refractive results. In addition, corneal aberrations induced by different techniques of lenticule extraction seemed similar to each other.

Sci-Thur AM: Planning - 10: Improved dosimetric accuracy for patient specific quality assurance using a dual-detector measurement method for cyberknife output factors.

The measurement of output factors for small fields is challenging and can lead to large dose errors in patient treatments if corrections for detector size and scatter from high-Z material are not applied. Due to its high spatial resolution and near tissue equivalence, GAFCHROMIC® film potentially provides a correction free measure of output factors but it can be challenging to obtain high quality dosimetric results using this film. We propose minimizing errors in the clinical determination of small field output factors by employing diode measurements with Monte-Carlo generated corrections for small fields ≤10 mm diameter and using small volume ion chambers for apertures >10 mm diameter with independent validation using radiochromic film. We performed patient specific quality assurance (QA) measurements for 9 patients using GAFCHROMIC® film and an A16 small volume ion chamber in a head-shaped phantom, employing this hybrid dual detector method for relative output factor measurements within the Multiplan treatment planning system. Our results suggest that consistent output factors can be determined using this method with experimental verification using GAFCHROMIC® film dosimetry. For the patient specific QA using film, we achieve good dosimetric agreement (<2σ) of the measured and calculated average dose for pixels within the 80% isodose line. For patient specific QA using the micro-ion chamber, we get good agreement (<3%) for cone sizes greater than 5 mm. The differences observed for the 5 mm cone plans are consistent with a 1 mm radial setup uncertainty for patient positioning using the Cyberknife system.

What is the impact of providing a transcatheter aortic valve implantation service on conventional aortic valve surgical activity: patient risk factors and outcomes in the first 2 years.

OBJECTIVES: To assess the impact of introducing a transcatheter aortic valve implantation (TAVI) service on aortic valve surgical activity and outcomes. DESIGN: A retrospective analysis of prospectively collected data. SETTING: University hospital of south Manchester. PATIENTS: 815 consecutive patients undergoing isolated aortic valve replacement (AVR) or coronary artery bypass grafting plus AVR from January 2006 to December 2009. Fifty consecutive patients who underwent TAVI from January 2008 to December 2009. MAIN OUTCOME MEASURES: Aortic valve surgical activity in the 2years before the introduction of a TAVI service and in the 2years following. Outcomes following conventional aortic valve surgery and TAVI. RESULTS: In the 2years following the introduction of TAVI at this centre, conventional AVR activity has increased by 37% compared with an 8% increase nationally (p<0.001). Compared with the 2years before TAVI there was no change in the mean logistic EuroSCORE (7.4 vs 7.9 p=0.16) or crude mortality rate (2.9% vs 2.1% p=0.48). Fifty high-risk patients underwent TAVI with a 30-day mortality rate of 0%. The mean logistic EuroSCORE of the TAVI patients was 25.3. CONCLUSIONS: TAVI is an emerging alternative to AVR in high-risk patients. Since the introduction of a TAVI service at this centre, conventional AVR activity has increased. Despite a trend of increasing mean logistic EuroSCORE indicating that more complex cases are being undertaken, there has been a non-significant reduction in the crude mortality rate. Offering a TAVI service has a positive impact on the volume of conventional AVR surgical activity.

Distribution of naturally occurring radionuclides activity concentration in East Malaysian marine sediment.

Studies of naturally occurring radioactive materials (NORM) distribution of (226)Ra, (228)Ra and (40)K in East Malaysia were carried out as part of a marine coastal environment project. The results of measurements will serve as baseline data and background reference level for Malaysia coastlines. Sediments from 21 coastal locations and 10 near shore locations were collected for analyses. The samples were dried, finely ground, sealed in a container and stored for a minimum of 30 days to establish secular equilibrium between (226)Ra and (228)Ra and their respective radioactive progenies. They were counted using a high-purity germanium (HPGe) spectrometer covering the respective progeny energy peak. For (40)K, the presence of this was measured directly via its 1460 keV energy peak. The concentration of (226)Ra, (228)Ra and (40)K in samples obtained from coastal Sarawak ranged between 23 and 41 (mean 30+/-2) Bq/kg, 27 and 45 (mean 39+/-4) Bq/kg and 142 and 680 (mean 462+/-59) Bq/kg, respectively. Meanwhile, the concentration of (226)Ra, (228)Ra and (40)K for samples obtained from coastal Sabah ranged between 16 and 30 (mean 23+/-2) Bq/kg, 23 and 45 (mean 35+/-4) Bq/kg and 402 and 842 (mean 577+/-75) Bq/kg, respectively. For the Sarawak near shore stations, the concentration of (226)Ra, (228)Ra and (40)K ranged between 11 and 36 (mean 22+/-2) Bq/kg, 21 and 65 (mean 39+/-5) Bq/kg and 149 and 517 (mean 309+/-41) Bq/kg, respectively. Meanwhile, the concentration of (226)Ra, (228)Ra and (40)K for samples obtained from Sabah ranged between 9 and 31 (mean 14+/-2) Bq/kg, 10 and 48 (mean 21+/-3) Bq/kg and 140 and 580 (mean 269+/-36) Bq/kg, respectively. The calculated external hazard values of between 0.17 and 0.33 (less than unity) showed that there is little risk of external hazard to the workers handling the sediments.

Hemodynamic performance of the 21-mm Sorin Bicarbon mechanical aortic prostheses using dobutamine Doppler echocardiography.

BACKGROUND: Small-sized mechanical aortic prostheses are commonly associated with generation of high transvalvular gradients, particularly in patients with large body surface area, and can result in patient-prosthesis mismatch. This study evaluates the hemodynamic performance of 21-mm Sorin Bicarbon bileaflet mechanical prostheses using dobutamine stress echocardiography. METHODS: Fourteen patients (7 women; mean age, 63+/-8 years) who had undergone aortic valve replacement with a 21-mm Sorin Bicarbon bileaflet mechanical prosthesis 32.4+/-5.1 months previously were studied. After a resting Doppler echocardiogram, a dobutamine infusion was started at a rate of 5 microg x kg(-1) x min(-1) and increased to 30 microg x kg(-1) x min(-1) at 15-minute intervals. Pulsed- and continuous-wave Doppler echocardiographic studies were performed at rest and at the end of each increment of dobutamine. Both peak and mean velocity and pressure gradient across the prostheses were measured, and effective orifice area, discharge coefficient, and performance index were calculated. RESULTS: Dobutamine stress increased heart rate and cardiac output by 83% and 81%, respectively (both p < 0.0001), and mean transvalvular gradient increased from 15.6+/-5.5 mm Hg at rest to 35.4+/-11.9 mm Hg at maximum stress (p < 0.0001). Although the indexed effective orifice area was significantly lower in patients with a larger body surface area, this was not associated with any significant pressure gradient. The performance index of this valve was unchanged throughout the study. Regression analyses demonstrated that the mean transvalvular gradient at maximum stress was independent of all variables except resting gradient (p = 0.05). Body surface area had no association with the changes in cardiac output, transvalvular gradient at maximum stress, and effective orifice area. CONCLUSIONS: These data show that the 21-mm Sorin Bicarbon bileaflet mechanical prosthesis offers an excellent hemodynamic performance with full utilization of its available orifice when implanted in the aortic position. The lack of significant transvalvular gradient in patients with a larger body surface area suggests that patient-prosthesis mismatch is highly unlikely when this prosthesis is used.

Patient-prosthesis mismatch is negligible with modern small-size aortic valve prostheses.

BACKGROUND: Concern has been raised about residual significant gradients when small aortic prostheses are used, particularly in patients with large body surface areas. We studied the performance of six types of small aortic prostheses using dobutamine stress echocardiography. METHODS: Sixty-three patients (mean age, 67 +/- 7 years) who had undergone aortic valve replacement 17 +/- 6 months previously were studied. Two bileaflet mechanical prostheses (St. Jude Medical and CarboMedics: sizes, 19 mm and 21 mm) and two biological prostheses (Medtronic Intact and St. Jude BioImplant: size, 21 mm) were evaluated. A graded infusion of dobutamine was given and Doppler studies of valve performance were carried out. RESULTS: All prostheses except one biological valve had acceptable hemodynamic performance under stress. Using regression modeling, gradient at rest was the only variable found to predict gradient under stress (p < 0.001). Moreover, the most important predictor of gradient at rest was valve design, which accounted for 72% of the variance (p < 0.001). This relationship was independent of valve size (19 mm or 21 mm) or material (ie, mechanical or biological). Body surface area accounted for 4% of the variance in gradient only. CONCLUSIONS: The main predictor of transprosthetic gradient is the inherent characteristics of each particular prosthesis, with relatively insignificant contribution from variations in body surface area. Patient-prosthesis mismatch is not a problem of clinical significance when certain modern valve prostheses are used.

Intraoperative localisation and management of coronary artery fistula using transesophageal echocardiography.

Coronary artery fistula is a rare congenital malformation that can be complicated by intracardiac shunts, endocarditis, myocardial infarction, coronary aneurysm and sudden death. Clinical symptomatology depends upon the underlying anatomy and the size of the fistulous connection between the left or right side of the heart. We report the successful management of a giant right coronary artery with fistulization into the right atrium. Intraoperative transesophageal echocardiography with colour flow Doppler was used for precise location of the fistulous communication, selective demonstration of vessels feeding the fistula and documentation of abolition of fistulous flow all without the need for cardiopulmonary bypass. Furthermore the effect of shunt occlusion on regional wall motion was documented which facilitated the successful ligation of the fistula.

Hemodynamic performance of the 21-mm St. Jude BioImplant prosthesis using dobutamine Doppler echocardiography.

This study examines the hemodynamic performance of small size St. Jude BioImplant aortic prostheses using dobutamine echocardiography. Eleven patients (3 women, mean age 75 years) who had undergone aortic valve replacement with a size 21-mm St. Jude BioImplant aortic prostheses at 10.8 +/- 5.1 months (SD) previously were studied. Dobutamine infusion was started at a rate of 5 microg/kg/min and increased to 10 microg/kg/min, and subsequently to 20 microg/kg/min at 15-minute intervals. Pulsed and continuous-wave Doppler studies were performed at rest and at the end of each stage. Effective orifice area, mean gradient, and the performance index across each prosthesis were calculated and cardiac output was determined by Doppler measurement of flow in the left ventricular outflow tract. Stress dobutamine increased heart rate and cardiac output by 51% and 56%, respectively (both p <0.0001), and the mean transvalvular gradient increased from 30.1 +/- 7.5 mm Hg at rest to 49.3 +/- 11.5 mm Hg at maximum stress (p <0.0005). The performance index increased progressively from 0.29 +/- 0.05 at rest to 0.40 +/- 0.10 at maximum stress (p <0.0005). Regression modeling analyses demonstrated that the maximum stress gradient was independent of all variables except the resting gradient (p = 0.03). Body surface area had no effect on the changes in cardiac output, effective orifice area, or transprosthetic gradient at maximum stress. Thus, these data demonstrate that the size 21-mm St. Jude BioImplant prosthesis exhibits suboptimal hemodynamic performance with transvalvular gradients consistent with mild to moderate aortic stenosis, both at rest and under stress conditions.

Dynamic evaluation of the 21-mm Medtronic Intact aortic bioprosthesis by dobutamine echocardiography.

BACKGROUND: High residual transvalvular gradients have been reported with the use of small Medtronic Intact aortic valve prostheses. The aim of this study was to evaluate the hemodynamic performance of 21-mm prostheses using dobutamine Doppler echocardiography. METHODS: Ten patients (7 women; mean age, 79 years) who had undergone aortic valve replacement with 21-mm Medtronic Intact prostheses 19.1 +/- 9.9 (standard deviation) months previously were studied. Dobutamine infusion was started at a rate of 5 microg x kg(-1) x min(-1) and increased to 10 and 20 microg x kg(-1) x min(-1) at 15-minute intervals. Pulsed and continuous-wave Doppler studies were performed at rest and at the end of each stage. Effective orifice area, performance index, and discharge coefficient of each valve were calculated, and peak and mean velocity and pressure drop across the prostheses were measured. Cardiac output was determined by Doppler measurement of flow in the left ventricular outflow tract. RESULTS: Dobutamine stress increased heart rate and cardiac output by 68% and 65%, respectively (both p < 0.005), and mean transvalvular gradient increased from 19.1 +/- 5.1 mm Hg at rest to 33.2 +/- 7.7 mm Hg at maximum stress (p < 0.0001). Regression analyses demonstrated that maximum-stress gradient was independent of all variables except resting gradients (p < 0.004). Body surface area had no effect on the changes in cardiac output, effective orifice area, or transprosthetic gradient at maximum stress. CONCLUSIONS: These data show that the 21-mm Medtronic Intact aortic prosthesis exhibits acceptable hemodynamic performance. Transvalvular gradients remained within a clinically acceptable range, both at rest and at maximum stress. Moreover, overall hemodynamic performance suggests that patient-prosthesis mismatch is unlikely to be a problem of clinical importance when this prosthesis is used.

Hemodynamics of St. Jude Medical prostheses in the small aortic root: in vivo studies using dobutamine Doppler echocardiography.

BACKGROUND AND AIMS OF THE STUDY: The well known correlation between prosthetic valve orifice area and transvalvular pressure drop has raised concerns about the presence of significant residual gradients when only a small-sized prosthesis can be implanted, particularly in patients with a large body surface area. The aim of this study was to study the hemodynamic performance of small-size St. Jude Medical aortic prostheses using dobutamine echocardiography. METHODS: Fifteen patients (14 females, one male, of mean age 67 years) who had undergone aortic valve replacement with size 19 mm St. Jude Medical prostheses at a mean of 19 +/- 8 (SD) months previously were studied. Dobutamine infusion was started at a rate of 5 micrograms/kg/min and increased to 10 and subsequently to 20 micrograms/kg/min at 15-min intervals. Pulsed and continuous-wave Doppler studies were performed at rest and at the end of each stage. Effective orifice area (EOA) and mean gradient across each prosthesis were calculated, and cardiac output (CO) was determined by Doppler measurement of flow in the left ventricular outflow tract. RESULTS: Dobutamine-stress increased heart rate and cardiac output by 57% and 86% respectively (both p < 0.0005), and mean transvalvular gradient increased from 22.0 +/- 4.9 mmHg at rest to 41.9 +/- 9 mmHg at maximum stress (p < 0.0001). Regression modeling analyses demonstrated that maximum stress gradient was independent of all variables except resting gradient (p = 0.0068). Body surface areas had no effect on the changes in cardiac output, effective orifice area or transprosthetic gradient at maximum stress. CONCLUSIONS: These data demonstrate that the size 19 mm St. Jude Medical prosthesis exhibits favorable hemodynamic performance. Transvalvular gradients remained within a clinically acceptable range, both at rest and under stress conditions. Moreover, in the patient population studied, overall hemodynamic performance indicates that with St. Jude Medical aortic valves, patient-prosthesis mismatch is unlikely to be a problem of clinical importance.