Isaac Kadir

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 2 years before the introduction of a TAVI service and in the 2 years following. Outcomes following conventional aortic valve surgery and TAVI. Results In the 2 years 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 2 years 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.

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.

Congenital unilateral pulmonary artery agenesis and aspergilloma.

Isolated unilateral pulmonary artery agenesis is a rare condition, which in most patients is asymptomatic. Occasionally patients present with symptoms that are nonspecific and not necessarily attributable to disease of the respiratory system. In these individuals the clue to the diagnosis is found in a plain chest roentgenogram, often revealing a hyperlucent contracted hemithorax. We present an unusual case of isolated unilateral pulmonary artery agenesis associated with the opportunistic organism Mycobacterium kansasii and Aspergillus fumigatus in which the diagnosis was made 10 years after initial presentation. Clinicians should be aware of this condition and include it in their differential diagnosis of a hyperlucent lung field on the chest roentgenogram.

Primary cardiac sarcoma: reports of two cases and a review of current literature

Primary cardiac sarcomas are rare tumors with an unfavourable prognosis. Complete surgical resection is currently the only mode of therapy proven to show any benefit. We report the cases of two patients presenting with features of obstruction and embolism and a presumed diagnosis of left atrial myxoma. At operation they were unexpectedly found to have large tumours raising strong suspicions of malignancy. Due to the extensive involvement of intracardiac structures with little possibility of reconstruction together with poor general condition of the patient, debulking was deemed to be the only viable option. Subsequent histology confirmed the diagnosis of sarcoma in both patients. Surgery produced immediate and effective symptom relief. The first patient died four months after the operation and second patient is still alive at 12 months after her operation. A brief review of literature on cardiac sarcoma is presented.

Conventional aortic valve replacement for high-risk aortic stenosis patients not suitable for trans-catheter aortic valve implantation: feasibility and outcome

OBJECTIVE High-risk patients with aortic stenosis are increasingly referred to specialist multidisciplinary teams (MDTs) for consideration of trans-catheter aortic valve implantation (TAVI). A subgroup of these cases is unsuitable for TAVI, and high-risk conventional aortic valve replacement (AVR) is undertaken. We have studied our outcomes in this cohort. METHODS Data prospectively collected between March 2008 and November 2009 for patients (n = 28, nine male) undergoing high-risk AVR were analysed. The mean age was 78.4 ± 9.2 years. The mean additive EuroSCORE (European System for Cardiac Operative Risk Evaluation) was 10.0 ± 3.6 and mean logistic EuroSCORE was 19.9 ± 18.8. Three patients had undergone previous coronary artery bypass grafting (CABG). RESULTS The mean ejection fraction was 51 ± 16%, mean valve area 0.56 ± 0.19 cm², and mean peak gradient 91 ± 27 mm Hg. Ascending aortic, right axillary artery and femoral artery cannulation was used in 64%, 29% and 7% of cases, respectively. Median cross-clamp and cardiopulmonary bypass times were 84 (68-143) min and 111 (94-223) min. The median (range) inserted valve size was 21 (19-25) mm. Median intensive care and overall hospital stay were 5 (2-37) and 11 (5-44) days, respectively. In-hospital mortality was 4% (one patient). Postoperative complications included re-operation for bleeding (7%), renal failure (21%), tracheostomy (14%), sternal wound infection (7%), atrial fibrillation (25%) and permanent pacemaker implantation (7%). Kaplan-Meier survival at median follow-up of 359 (148-744) days was 81% (one further death of non-cardiac aetiology). Quality-of-life assessment at follow-up also yielded satisfactory results. CONCLUSIONS MDT assessment of high-risk aortic stenosis in the era of TAVI has increased the number of referrals. Conventional open surgery remains a valid option for these patients, with acceptable in-hospital mortality and early/midterm outcomes but high in-hospital morbidity.

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.

Recurrent acute rheumatic fever: a forgotten diagnosis?

The incidence of acute rheumatic fever has seen a dramatic decline over the last 15 to 20 years in most developed countries and treatment of this disease has changed little since. The ease of travel and immigration and the cosmopolitan nature of many cities mean that occasionally the disease will come to the attention of clinicians not familiar with its presentation, resulting in delayed diagnosis and treatment. We present a case of recurrent acute rheumatic fever in a patient who was initially thought to be suffering from acute bacterial endocarditis on her previously diseased rheumatic aortic valve. This culminated in her undergoing urgent aortic valve replacement during a phase of the illness that should have been treated with high dose anti-inflammatory medication. Therefore, clinicians should be aware of this condition and include it in their differential diagnosis of the febrile patient with a previous history of rheumatic fever. We briefly discuss the diagnostic dilemma of patients suffering from this condition and in differentiating it from acute endocarditis.

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.

Scrotal Distension After Endoscopic Harvesting of the Saphenous Vein in Patients With Inguinal Hernia

The great saphenous vein remains the most commonly used conduit for coronary artery bypass grafting. The endoscopic vein harvesting technique is widely used due to reduced postoperative complications. We present the case of 5 patients with a history of inguinal hernia undergoing coronary artery bypass grafting, which resulted in CO2 infiltration through the deep inguinal ring and into the scrotum leading to acute scrotal enlargement. Due to the risk of impediment of vascular blood supply and necrosis, endoscopic vein harvesting was withdrawn, and the vein was harvested by using the bridging technique. Postoperatively, severe contusion, inflammation, and erythematous vesicular eruption resulted in a lengthened hospital stay.

Hemi-Cabrol Aortic Root Replacement in Complex Aortic Reconstructions

The Cabrol aortic root replacement with subsequent modifications remains an extremely useful technique within the armamentarium of the aortic surgeon. The technical considerations detailed here allow for the uncompromised creation of a hemi-Cabrol anastomosis in complex aortic reconstructions.