Quick Links
- Bedside Echo
- Acute Coronary Syndromes
- Angiography
- Atrial Fibrillation
- AF Ablation
- Sudden Death Syndromes
- Lead Extraction
- Communication
- TAVI
- Coronary Artery Bypass Grafting
Bedside Echo
Stop the press: pocket echo machines are OK-ish, in a vague sort of way, with lots of qualifications (how does this stuff get published?).
M Llebo and others. Ann Intern Med. 2011;155:33-38.
Acute Coronary Syndromes
Yet another drug for reducing ischaemic outcomes in ACS patients? Sadly, or maybe even gladly, not, according to the APPRAISE 2 trial. Apixaban, a direct factor Xa inhibitor used in thromboembolism prophylaxis and atrial fibrillation (AF) (others include dabigatran and rivaroxaban) only managed to increase bleeding in high risk ACS patients when added to standard dual antiplatelet therapy, with no significant reduction in ischaemic events. This seems to continue the trend that oral anticoagulants have little overall benefit in ACS (warfarin, hirudin), whilst oral antiplatelet agents (aspirin, clopidogrel, prasugrel, ticagrelor), subcutaneous anticoagulants (enoxaparin, fondaparinux) and intravenous antiplatelet (glycoprotein IIB IIIA inhibitors) and anticoagulants (bivalirudin) do.
J Alexander and others. NEJM. 2011;10.1056/NEJMoa1105819.
Good to know that cardiovascular drugs are also beneficial in patients with chronic kidney disease (CKD). The SHARP trial randomised 9270 patients with CKD and no previous history of MI or coronary revascularisation to simvastatin 20mg plus ezetimibe 10mg daily versus matching control. The primary outcome of first major atherosclerotic event (a combination of non-fatal MI or coronary death, non-haemorrhagic stroke, or any arterial revascularisation procedure) was significantly reduced with the active drugs (11.3% vs. 13.%) that reduced the average LDL cholesterol by 0.85mmol/L. Another high risk group that needs targeting and treatment.
C Baigent and others. Lancet. 2011;377:2181-92.
Angiography
A fairly disturbing registry in America showed that the likelihood of finding obstructive coronary artery disease on elective diagnostic angiography varies from 23% to 100% (median 45%). The data was collected through the huge National Cardiovascular Data Registry (NCDR) from 565,504 patients with known coronary artery disease, undergoing angiography at 691 centres, between 2005 and 2008. The data raises more questions than it answers, but suggests that some clinicians and centres significantly overestimate angiographic stenosis, or do not have a sufficiently low enough threshold to perform angiography in patients with symptoms of coronary disease, whilst other individuals and centres are doing the exact opposite. It is important to note that the health service in the US is privately funded (land of the free?) and a number of interventionists have recently had their licences revoked or have received jail sentences for inappropriate PCI and/or billing. We still do not know the correct ‘hit rate’, but the current guidelines for appropriate indications for revascularisation, good history taking, assessment of risk factors, non-invasive and pressure wire FFR assessment for ischaemia seem like a good place to start.
PS Douglas and others. J Am Coll Cardiol. 2011;58:801-809.
Atrial Fibrillation
Another factor Xa inhibitor, rivaroxaban has shown more positive results in patients with atrial fibrillation (AF). In the ROCKET AF trial patients with AF were randomised to rivaroxaban or warfarin, with non-inferiority demonstrated for the prevention of stroke or systemic embolism. There was a significant reduction in intracranial haemorrhages and fatal bleeding in the rivaroxaban group, though these results were (part of) a secondary endpoint and should be interpreted with caution. Good news and less hassle for patients who do not need INR monitoring with rivaroxaban. The financial cost and subsequent European approval for AF is now awaited. It will also be competing with dabigatran.
MR Patel and others. NEJM. 2011. 10.1056/NEJMoa1009638.
AF ablation
Attempting to ablate AF in patients with unresolved valvular heart disease is well known to be challenging, but how do patients do with AF ablation post valve replacement? Two series of a total of 130 patients with prosthetic Aortic and Mitral valves, compared with matched non valvular patients produced similar results. Acceptable overall success rates (first procedure about 50%, 80% after mean 1.3 procedures), a high rate of atrial flutter both pre and post ablation and efficacy of linear ablation in preventing arrhythmia recurrence. Trends were observed toward higher complication rates and longer procedure and fluoroscopy times in the valvular group.
D Lakkireddy and others. Heart Rhythm. 2011;8:975–980.
A Hussein and others. J Am Coll Cardiol. 2011; 58:596-602.
A big concern in AF ablation is stroke risk. Measures are taken to avoid performing the procedure in the context of pre existing thrombus, but generation of embolic material during the procedure cannot be entirely prevented. A comparison of three ablation modalities (irrigated radiofrequency, Cryo and non irrigated phased RF) with MRI brain follow up revealed a much higher incidence of sub clinical cerebral infarcts in the non irrigated group (7.4 vs. 4.3 vs. 37.5%).
Two cautions with these data. Firstly, these are not strokes, they are an asymptomatic radiological finding (there were no clinical strokes). Secondly, a proportion of the energy delivered in the non irrigated phased RF group was done so in a fashion not recommended by the manufacturer and known to be associated with increased char and micro bubble formation.
C Siklody and others. J Am Coll Cardiol. 2011;58;681-688.
Sudden Death Syndromes
We still don’t really know what to do about early repolarisation syndrome yet, so two new contributions are welcome. Japanese atom bomb survivors get regular medicals including 12 lead ECGs. Headline findings are that early repolarisation is common (23% lifetime incidence with a peak first manifestation in the late second and early third decade), has a significant cross over with Brugada syndrome and is associated with a modest overall increase in sudden death rate (HR 1.8 vs. controls, in comparison to Brugada ECGs HR 27.5). Widespread abnormalities (slurring and/or notching) were associated with higher rates of sudden cardiac death.
It does seem clear that early repolarisation is at best a spectrum and possibly no more than a hotchpotch of vaguely connected conditions. In an attempt to split out higher and lower risk phenotypes a Finnish group examined various cohorts (Finnish athletes, US athletes and a middle aged group). They conclude that in early repolarisation (notching or slurring of the terminal QRS) where the ST segments are upsloping there is no increased risk of SCD and this represents a normal finding particularly prevalent in athletes. Where early repolarisation is associated with a down sloping ST segment there was some increased risk of SCD (albeit modest, RR 1.43).
D Haruta and others. Circulation. 2011;123:2931-2937.
J Taikkanen and others. Circulation. 2011;123:2666-2673.
Short QT syndrome is the other end of the spectrum; very rare, highly malignant. The European registry includes just 53 patients, follow up on this highly selected group, 89% of whom have personal or family histories of SCD reveals two findings. Firstly, they have a lot of arrhythmias (4.9% per year if untreated). Secondly, Hydroquinidine is effective in reducing the event rate (no events in the 12 patients treated).
C Giustetto and others. J Am Coll Cardiol, 2011; 58:587-595
Lead Extraction
Lead extraction is often considered a special case among percutaneous procedures with perceptions of high mortality and high rates of surgical intervention. Indeed some have advocated all such procedures being performed in cardiothoracic theatre to facilitate earliest possible surgical intervention.
In this series of 1364 leads in 864 consecutive patients the authors studied the differences in outcome between procedures performed in theatre and in the cath lab. The findings were of an overall mortality of 0.2%, with surgical interventions required at some stage in 0.9%. The only two massive haemorrhages due to SVC laceration died despite surgical intervention. Older leads were independently associated with increased complications, 92% of leads were extracted in their entirety. There were no differences in outcomes between patients extracted in theatre vs. those extracted in the EP lab. One patient underwent unproductive surgical exploration for a transient blood pressure drop, but did fine despite this.
F Freceschi and others. Heart Rhythm 2011;8:1001–1005.
Communication
Is it good to talk? When we quote figures on risks and benefits to patients, what are we trying to achieve? Do we just want to write something in the notes to cover ourselves or do we really want to help the patient understand?
A survey of what patients took in from written and diagrammatic explanations challenges perceived wisdom and existing guidelines. Patients do understand (sort of) low risk expressed as very small percentages (e.g. less than 1%, 0.02%) which we are supposed to avoid but do not understand numerator/denominator comparisons especially where the denominator changes (e.g. risk of stroke 1 in 100, risk of death 2 in 1000). Furthermore, patients understand absolute risk and changes therein much better than relative risk.
S Woloshin and others. Ann Intern Med. 2011;155:87-96.
How about communication between district hospital interventional cardiologists and surgeons at a remote surgical centre? Apparently a video link system in Sussex significantly increased the number of patients with complex coronary disease having surgical revascularisation rather than PCI. We have mixed views on this. Cardiothoracic surgeons, in the main, will perform coronary artery bypass grafting (CABG) on elective patients, even when high risk, if they have appropriate coronary disease. The problems come with acutely unwell patients, when shock, renal dysfunction or troponin elevation seem to put them off! The SYNTAX study (CABG vs. PCI in high risk coronary artery disease) and ongoing trans-aortic valve implantation (TAVI) programmes have certainly improved relations between cardiothoracic surgeons and interventionists, and this must be a good thing.
R.A Veasey and others. Int J Clin Pract. 2011;65:658-663.
TAVI
Having mentioned TAVI, it would be remiss of us not to comment on the one year results of the SOURCE registry, which has reported the outcomes of 1038 patients enrolled at 32 centres undergoing implantation of the Edwards SAPIEN aortic valve, either transapically (575 patients) or transfemorally (463 patients). Transapical TAVI is performed in those patients with peripheral vascular disease, whom represent a higher risk group at baseline (logistic EuroSCORE 29% for transapical vs. 25.8% for transfemoral). Total one year survival was 76.1% overall, with 72.1% for transapical and 81.1% for transfemoral. Impressive results, that are only going to improve as the experience and the kit gets better.
M Thomas and others. Circulation. 2011 124:425-433.
Coronary Artery Bypass Grafting
And whilst we are talking about cardiothoracic surgeons, we should briefly mention this study looking at saphenous venous grafts in patients undergoing CABG (PREVENT IV trial). Essentially, vein graft failure is significantly worse at one year if there are multiple rather than single distal targets (something to do with flow presumably?). This results in a significantly poor clinical outcome at five years (worse composite of death, MI or revascularisation), so is best avoided.
