Effect of Transcatheter Aortic Valve Implantation vs Surgical Aortic Valve Replacement on All-Cause Mortality in Patients With Aortic Stenosis: A Randomized Clinical Trial

IMPORTANCE

Transcatheter aortic valve implantation (TAVI) is a less invasive alternative to surgical aortic valve replacement and is the treatment of choice for patients at high operative risk. The role of TAVI in patients at lower risk is unclear.

OBJECTIVE

To determine whether TAVI is noninferior to surgery in patients at moderately increased operative risk.

DESIGN, SETTING, AND PARTICIPANTS

In this randomized clinical trial conducted at 34 UK centers, 913 patients aged 70 years or older with severe, symptomatic aortic stenosis and moderately increased operative risk due to age or comorbidity were enrolled between April 2014 and April 2018 and followed up through April 2019.

INTERVENTIONS

TAVI using any valve with a CE mark (indicating conformity of the valve with all legal and safety requirements for sale throughout the European Economic Area) and any access route (n = 458) or surgical aortic valve replacement (surgery; n = 455).

MAIN OUTCOMES AND MEASURES

The primary outcome was all-cause mortality at 1 year. The primary hypothesis was that TAVI was noninferior to surgery, with a noninferiority margin of 5% for the upper limit of the 1-sided 97.5% CI for the absolute between-group difference in mortality. There were 36 secondary outcomes (30 reported herein), including duration of hospital stay, major bleeding events, vascular complications, conduction disturbance requiring pacemaker implantation, and aortic regurgitation.

RESULTS

Among 913 patients randomized (median age, 81 years [IQR, 78 to 84 years]; 424 [46%] were female; median Society of Thoracic Surgeons mortality risk score, 2.6% [IQR, 2.0% to 3.4%]), 912 (99.9%) completed follow-up and were included in the noninferiority analysis. At 1 year, there were 21 deaths (4.6%) in the TAVI group and 30 deaths (6.6%) in the surgery group, with an adjusted absolute risk difference of -2.0% (1-sided 97.5% CI, -∞ to 1.2%; P < .001 for noninferiority). Of 30 prespecified secondary outcomes reported herein, 24 showed no significant difference at 1 year. TAVI was associated with significantly shorter postprocedural hospitalization (median of 3 days [IQR, 2 to 5 days] vs 8 days [IQR, 6 to 13 days] in the surgery group). At 1 year, there were significantly fewer major bleeding events after TAVI compared with surgery (7.2% vs 20.2%, respectively; adjusted hazard ratio [HR], 0.33 [95% CI, 0.24 to 0.45]) but significantly more vascular complications (10.3% vs 2.4%; adjusted HR, 4.42 [95% CI, 2.54 to 7.71]), conduction disturbances requiring pacemaker implantation (14.2% vs 7.3%; adjusted HR, 2.05 [95% CI, 1.43 to 2.94]), and mild (38.3% vs 11.7%) or moderate (2.3% vs 0.6%) aortic regurgitation (adjusted odds ratio for mild, moderate, or severe [no instance of severe reported] aortic regurgitation combined vs none, 4.89 [95% CI, 3.08 to 7.75]).

CONCLUSIONS AND RELEVANCE

Among patients aged 70 years or older with severe, symptomatic aortic stenosis and moderately increased operative risk, TAVI was noninferior to surgery with respect to all-cause mortality at 1 year.

TRIAL REGISTRATION

isrctn.com Identifier: ISRCTN57819173.

Anterior leaflet replacement and reconstruction with Admedus Cardiocel™ decellularized pericardial patch in tricuspid valve endocarditis

We present the case of a 28 year-old lady with a history of intravenous drug use who presented to our institution with symptomatic right heart failure secondary to tricuspid valve regurgitation. She presented with infective endocarditis leading to dyspnoea and peripheral oedema secondary to torrential tricuspid regurgitation. Transthoracic echocardiography confirmed right ventricular dysfunction and congestive hepatomegaly. Intra-operatively findings an infected and destroyed anterior leaflet of the tricuspid valve with posterior leaflet prolapse was found to cause severe tricuspid regurgitation. She had complex tricuspid valve reconstruction using anterior leaflet reconstruction using Admedus Cardiocel™ patch, posterior leaflet prolapse correction and commissural reduction with a McGoon imbrication and annuloplasty ring to stabilize the repair. This case demonstrates the importance of reconstructive tricuspid valve surgery in the setting of infective endocarditis. Furthermore, this case demonstrates the possibility of anterior leaflet excision and reconstruction with an excellent durable functional result.

Silzone-coated St. Jude Medical valves: six-year experience in 46 patients

BACKGROUND AND AIM OF THE STUDY

The Silzone-coated St. Jude Medical valve was developed to reduce prosthetic valve endocarditis, but in the Artificial Valve Endocarditis Trial (AVERT) was recalled following reports of major paravalvular leaks. A separate study suggested an increased risk of thromboembolic complications associated with the Silzone valve. Herein is reviewed the present authors' experience in patients with Silzone valves.

METHODS

Between April 1998 and November 1999, 46 patients (28 males, 18 females; mean age 62.6 years; range: 41-78 years) received a total of 49 Silzone valves. Seven of the patients were in NYHA class IV, and 29 in class III; four patients had active endocarditis. Twenty-one patients underwent aortic valve replacement, 22 mitral valve replacement, and three had both mitral and aortic valve replacement. Concomitant procedures were performed in nine patients.

RESULTS

The 30-day mortality was 6.5 % (n = 3). At post-mortem examination, the valves were found to be seated well, with no evidence of malfunction, thrombotic occlusion or infection. Follow up examinations were conducted initially at six months after surgery, and annually thereafter. All patients underwent transthoracic echocardiography. Follow up was 100% complete; the mean follow up period was 73.5 months (range: 62-81 months). Six late deaths have occurred; five deaths were due to non-cardiac causes, and one cardiac death was unrelated to the valve prosthesis. No cases of paravalvular leak have been identified. Two patients had postoperative thromboembolic complications, but echocardiography did not demonstrate the presence of thrombus or paravalvular leakage.

CONCLUSION

In this single-center, non-randomized study of 46 patients, the findings of increased paravalvular leak with the Silzone valve, as identified in AVERT study, could not be confirmed. Moreover, the incidence of thromboembolic complications reported was modest.

Use of intraventricular ribbon gauze to reduce particulate emboli during aortic valve replacement

Background

The incidence of cerebrovascular accidents following aortic valve surgery remains a devastating complication. The aim of this study was to determine the number of potential embolic material arising during aortic valve replacement and to examine the efficacy of using ribbon gauze in the left ventricle during removal of the native valve and decalcification of the aortic annulus.

Methods

Ribbon gauze was inserted into the left ventricular cavity prior to aortic valve excision in an unselected, prospectively studied series of 30 patients undergoing aortic valve replacement. A further 30 lengths of ribbon gauze were soaked in the pericardiotomy blood of the same patients and all were subjected to histological analysis.

Results

The median number of tissue fragments from the aortic valve replacement group was significantly higher than in the control group 5 (0–18) versus 0 (0–1) (p = 3.6 × 10^-5). The size of tissue fragments varied between 0.1 and 9.0 mm with a mean of 0.61 ± 1.12 mm and a median of 0.2 mm. There was a significantly higher number of tissue fragments associated with patients having surgery for aortic stenosis when compared with patients who had aortic regurgitation with median of 5 (0–18) versus 0 (0–3) (p = 0.8 × 10^-3).

Conclusion

Significant capture of particulate debris by the intraventricular ribbon gauze suggests that the technique of left ventricular ribbon gauze insertion during aortic valve excision has merit.

Sutureless off-pump repair of post-infarction left ventricular free wall rupture

Left ventricular free wall rupture after myocardial infarction has a high mortality. Suturing techniques of repair may be technically difficult and require cardiopulmonary bypass. We report a case of left ventricular rupture in a 47 year old man managed off pump employing a sutureless technique with Gelatine-Resorcin-Formalin glue and bovine pericardial patches.

Left ventricular false aneurysm after previous repair of acquired ventricular septal defect

We report a novel case of a 69-year-old woman who was treated surgically for a postinfarction inferior ventricular septal defect and presented 3 years postoperatively with a large left ventricular false aneurysm. This was successfully repaired.

Oesophageal epiphrenic diverticulum: an unusual presentation and review

Epiphrenic pulsion diverticula are rare and often asymptomatic. We describe a case presenting in an unusual fashion, and review the controversy over the management of this condition with regard to the requirement for myotomy and antireflux surgery. We believe that both procedures are necessary, but believe that both procedures are necessary, but optimal management strategies are unlikely to be resolved as the rarity of the condition precludes largescale prospective studies.

Adult congenital lobar emphysema in pregnancy

A young woman presented with left sided chest pain. Chest radiography revealed a hyperexpanded left upper lobe and the rare diagnosis of congenital lobar emphysema was made. She was then found to be pregnant. Thoracotomy and left upper lobectomy were performed during the pregnancy without adverse effects to the mother or fetus. The implications of pregnancy on the surgical management of this rare condition are discussed.

Anions, membrane resistance and ventricular fibrillation

Clinical success in prevention of sudden cardiac death has been poor. New approaches to prevention of ventricular fibrillation (VF), one of the main causes of sudden cardiac death, are clearly needed. In the present article we have reviewed some of our own data which support the notion that VF may be prevented by manipulation of chloride homeostasis. Our studies have revealed a novel approach to VF suppression via alteration of sarcolemmal membrane resistance.

Spontaneous rupture of a congenital diaphragmatic eventration

A 51-year-old man presented as an emergency with acute intestinal obstruction following herniation of abdominal contents into the left hemithorax through a spontaneous rupture of his eventrated left hemidiaphragm. He underwent a left thoracotomy with reduction of the herniated abdominal contents, repair of the diaphragmatic rupture and plication of the diaphragm. He made an uneventful recovery and remains asymptomatic. This is the first reported case of spontaneous rupture of an eventration of the diaphragm.

Anion manipulation, a novel antiarrhythmic approach: mechanism of action

We recently reported that modulation of anion homeostasis by substitution of extracellular chloride by nitrate prevents ischaemia- and reperfusion-induced ventricular fibrillation (VF) in rat and rabbit in vitro by an unknown mechanism independent of haemodynamic changes but related to widening of QT interval (Ridley and Curtis 1991). In the present study we have examined three possible explanations for the mechanism: modification of membrane anion permeability, alteration of cyclic nucleotide homeostasis and alteration of intracellular pH. In isolated Langerdorff-perfused rat heart (n = 12/group), substitution of chloride in modified Krebs perfusion solution by anion surrogates (methylsulphate, bromide, nitrate or iodide) inhibited left regional ischaemia- and reperfusion-induced arrhythmias only when the membrane permeability of the surrogate was greater than that of chloride (e.g., nitrate, bromide, iodide); the least permeant anion, methylsulphate, was proarrhythmic during ischaemia. Rank order of arrhythmia susceptibility correlated with the relative permeability of each anion, with near abolition of both ischaemia- and reperfusion-induced VF (P < 0.05) by the most permeant anions (iodide and nitrate). Arrhythmia suppression occurring in the iodide and nitrate groups was accompanied by significant widening of QT interval at 90% repolarization, with effects substantially more marked during ischaemia than before ischaemia. In separate studies using the same model we determined cardiac cyclic (c) AMP and cGMP content and their molar ratios by radioimmunoassay of biopsies before, during and after ischaemia. There was no meaningful relation between cyclic nucleotide content and rank order of arrhythmia susceptibility ruling out changes in the former as a contributory mechanism to the latter. In further studies we measured intracellular pH in the isolated perfused rat heart by phosphorus NMR spectroscopy. Nitrate caused a slight intracellular acidosis which was exacerbated when hearts were made globally ischaemic, indicating that its antiarrhythmic activity was not a consequence of alkalinisation (e.g., via inhibition of chloride-bicarbonate exchange). To test for inherent adverse effects on cardiac contractile function we analysed Starling curves in isolated rat hearts perfused under conditions equivalent to those used for arrhythmia studies. There was no relationship between perfusion anion composition and systolic (developed pressure at constant intraventricular volume, and pressure-volume slope) or diastolic function (end-diastolic pressure at constant intraventricular volume). In conclusion, alteration of membrane permeability is a mechanism which may be sufficient to explain modulation of arrhythmias by manipulation of extracellular anion content, appears to be devoid of deleterious effects on contractile function, and may represent a focus for future antiarrhythmic drug development.

Heterotopic heart transplantation and recipient heart operation in ischemic heart disease

The role of heterotopic heart transplantation in coronary heart disease has not been defined. Between 1983 and 1988, 28 patients with end-stage ischemic heart disease were managed by heterotopic heart transplantation and adjunctive operation on the recipient heart: coronary artery bypass grafts and aneurysmectomy, 20; coronary artery bypass grafts, 5; and aneurysmectomy, 3. Indications were feasibility of operative procedures to the recipient heart and small donor size (61% of the donors were less than 15 years). The 1-year and 5-year actuarial survival was 79% and 63%. Of the 22 patients who survived to 2-year follow-up, all of whom had been severely limited (New York Heart Association grade III/IV) preoperatively, 20 were in grades I or II at 2-year follow-up (p less than 0.001). In 14 of 22 patients (64%), the recipient heart augmented the donor cardiac output substantially, and in 4 the recipient heart supported the patient when the donor heart failed to eject. In conclusion, this series demonstrates the efficacy of heterotopic transplantation combined with operation to the recipient heart in the management of patients with end-stage ischemic heart disease.

A modified model of global ischaemia: application to the study of syncytial mechanisms of arrhythmogenesis

OBJECTIVE

The aim was to develop a simple modified global ischaemia preparation to study the relation between ischaemic zone size and the incidence of ischaemia induced and reperfusion induced arrhythmias, to test the hypothesis that arrhythmias are initiated by flow of injury current between the ischaemic zone and the uninvolved myocardium. The new model was used to examine whether injury current suppression is involved in the mechanism of action of a new antiarrhythmic intervention, substitution of chloride anion by nitrate.

METHODS

Isolated perfused (Langendorff mode) rat hearts (n = 12 per group) were subjected to 30 min global or regional ischaemia. Ventricular arrhythmia incidence during ischaemia and during reperfusion were related to the size of the involved region. The modified model of global ischaemia employed right intra-atrial superfusion to maintain normal sinus rate and 1:1 atrioventricular (AV) conduction.

RESULTS

Sham ligation, low left coronary ligation, high left coronary ligation, and global ischaemia produced, as a percentage of total ventricular weight, 0%, 21.0(SEM 0.8)%, 47.0(1.0)%, and 100% regions of ischaemia (occluded zones). Heart rates were similar in each group and AV block did not occur. The incidences of ischaemia induced ventricular fibrillation (VF) were 0, 17, 75, and 17% with increasing occluded zone sizes. Incidences of reperfusion induced VF were 0, 8, 92, and 92% respectively. The antiarrhythmic action of substitution of extracellular chloride by nitrate, previously shown using models of regional ischaemia, was confirmed in the modified global ischaemia model.

CONCLUSIONS

These findings strongly support the theory that current of injury between ischaemia and adjacent non-ischaemic zones is necessary for initiation of ischaemia induced VF, since susceptibility was maximal when ischaemic and uninvolved regions were equivalent in size (and the scope for injury current was maximal) whereas susceptibility was negligible when scope was minimal. In contrast, reperfusion induced VF appears to depend only on the presence and amount of reperfused tissue, indicating that flow of injury current between involved and uninvolved tissue is unnecessary for its initiation. Discrimination of the mechanism of action of antiarrhythmic interventions may be possible since drugs effective solely via amelioration of flow of injury current (or incrementation of collateral flow) will not influence arrhythmias in this model. Modification of injury current and collateral flow do not appear to contribute to the antiarrhythmic action of substitution of extracellular chloride by nitrate.

Anion manipulation: a new antiarrhythmic approach. Action of substitution of chloride with nitrate on ischemia- and reperfusion-induced ventricular fibrillation and contractile function

The role of anions in the initiation of ischemia- and reperfusion-induced arrhythmias is unknown. We examined the antiarrhythmic effects of isotonic substitution of extracellular Cl- with NO3- by using the rat Langendorff preparation (n = 12 per group). During 30 minutes of regional ischemia, the incidence of ventricular fibrillation (VF) was reduced from 50% in hearts perfused with control solution (containing a Cl-:NO3- ratio of 100:0) to 25%, 0% (p less than 0.05), 0% (p less than 0.05), and 0% (p less than 0.05) by perfusion with solution containing Cl-:NO3- ratios of 75:25, 50:50, 25:75, and 0:100, respectively. The incidence of reperfusion-induced VF was also reduced from 58% to 25%, 8% (p less than 0.05), 8% (p less than 0.05), and 0% (p less than 0.05), respectively. Similar effects were produced in hearts reperfused after briefer durations of ischemia (10 or 15 minutes). Substitution of NO3- for Cl- also facilitated spontaneous termination of VF. Heart rate and occluded zone size were not affected by anion manipulation. Coronary flow was affected by NO3-, but changes did not correlate with arrhythmias. During ischemia, electrocardiographic changes indicative of class III activity (widening of the ventricular complex) were produced by anion substitution. These changes occurred selectively in the ischemic tissue with no significant influence before ischemia onset. However, the relation between this effect and arrhythmia reduction was not linear and a cause-effect relation is therefore unlikely. In separate groups of hearts (n = 12 per group), switching from 100:0 to 0:100 Cl-:NO3- solution or vice versa 10 seconds after coronary occlusion or just before reperfusion demonstrated that 1) protection against ischemia-induced VF resulted partly from an action in the ischemic zone and partly from an action in the nonischemic zone, and 2) protection against reperfusion-induced VF resulted principally from an action occurring during reperfusion and within the reperfused tissue. To assess whether benefit was offset by deleterious effects on contractile function in nonischemic tissue, we constructed Starling curves in isolated rate hearts. The 0:100 Cl-:NO3- solution had no effect on compliance or contractility at physiological end-diastolic pressures but reduced the slope of the peak systolic pressure-volume relation by approximately 20% as end-diastolic pressure was increased above 10 mm Hg. In conclusion, anions appear to play a hitherto unrecognized role in arrhythmogenesis in ischemia and reperfusion. Manipulation of anion homeostasis may represent a novel target for antiarrhythmic drug development.

Primary sarcoma of the lung: potential dangers of immunocytochemistry

A case is presented of a successfully resected primary pulmonary sarcoma in a 27-year-old man, followed by an eight-year disease-free follow-up. Details of the histological findings are presented, and the factors associated with good prognosis discussed. Immunocytochemical stains were carried out this year when the case was reviewed, and not at the time of resection. Had the immunostains been available at the time, the results would have suggested that the tumour might be a secondary deposit, and so have caused needless anxiety to the patient and his physicians.

The metabolic consequences of a "washed" cardiopulmonary bypass pump-priming fluid in children undergoing cardiac operations

The substrate load of the pump-priming fluid, especially glucose and lactate, has a major influence on the metabolic response of children during cardiac operations and may be detrimental neurologically. It is possible to cleanse the priming fluid of these excess substrates by ultrafiltration followed by the addition of a balanced electrolyte solution. We have used this technique in the bypass management of nine children over 1 year of age and weighing less than 18 kg who were studied from induction of anesthesia to 6 hours postoperatively. Frequent blood samples were taken for measurement of electrolytes, intermediary metabolites, and stress-related hormones. Throughout the study period electrolyte concentrations were maintained within the physiologic range and changes in blood glucose and lactate were minimized compared with those of matched historical controls from previous studies. During the period of cardiopulmonary bypass mean serum glucose concentrations varied between 4.4 and 7.7 mmol/L and peaked at 10.7 mmol/L just before skin closure. The mean serum lactate concentration did not exceed 2.3 mmol/L during the period studied. Thus ultrafiltration of the priming fluid and replacement with a balanced electrolyte solution results in the delivery to the patient of a reasonably physiologic substrate load, which is reflected in improved control of mean plasma intermediary metabolite concentrations. The method may form the basis of further clinical studies to determine specific aspects of the metabolic stress response in children.

Protein C deficiency associated with massive cerebral thrombosis following open heart surgery

We describe a case of massive cerebral venous thrombosis following open heart surgery in a patient with a reduced level of Protein C (40% of mean level). Protein C deficiency is an inherited disorder which in the homozygous form may result in massive fatal venous thrombosis in the newborn. A Protein C level below 55% is highly suggestive of heterozygous deficiency and has been associated with a tendency to venous thrombosis although its clinical penetrance is variable. This is the first reported case of massive venous thrombosis in a patient following open heart surgery associated with Protein C deficiency.

Comparative evaluation of cefotaxime and cephamandole in the prevention of post-operative infective complications following emergency abdominal surgery

In previous published work we described 57 patients undergoing emergency abdominal surgery, prospectively randomised to receive either cefotaxime or cephamandole as a single-antibiotic, three-dose, peri-operative prophylaxis against post-operative infective complications. This earlier work suggested that cefotaxime might be more effective than cephamandole in preventing wound sepsis in emergency abdominal surgery. We describe here our findings in a further 63 patients undergoing emergency abdominal surgery who were similarly allocated into either a cefotaxime or cephamandole antibiotic group. Infective complications occurred in 12/32 (37 per cent) of the cefotaxime group and 15/31 (48 per cent) of the cephamandole group. Wound infections occurred in 5/32 (16 per cent) of the cefotaxime group and 9/31 (29 per cent) of the cephamandole group. The organisms cultured and their sensitivities are discussed in detail. The total of 120 patients studied in the two series showed wound infection to occur in 13 per cent of the 62 patients receiving cefotaxime and 30 per cent of the 58 patients receiving cephamandole. This difference reaches statistical significance (p less than 0.05). Possible mechanisms to explain this finding are discussed. Again we found the regime of 4 g of cefotaxime given peri-operatively to be a simple, safe and effective single agent as prophylaxis for emergency abdominal surgery.

Rupture of a pseudoaneurysm of a saphenous vein coronary arterial bypass graft presenting with superior caval venous obstruction

We describe the first reported case of rupture of a pseudoaneurysm of a sapheneous vein coronary arterial bypass graft presenting with acute superior caval venous obstruction. The patient was successfully treated by urgent surgical excision of the graft.