Valvular Atrial Fibrillation With HF Common, Often Untreated in Young Africans

Marlene Busko

June 07, 2016

MEXICO CITY, MEXICO — One in five patients admitted to the hospital with acute heart failure in sub-Saharan Africa had atrial fibrillation (AF), and half of those with AF had rheumatic valve disease, a new study reports[1].

Compared with heart-failure patients in developed countries, sub-Saharan patients were 20 years younger. At 6 months, only 22% were on warfarin, which meant the rest were at increased risk of stroke; and the risk of dying doubled for those with valvular rather than nonvalvular AF.

Dr Mahmoud Umar Sani (Bayero University and Aminu Kano Teaching Hospital, Kano, Nigeria) presented these findings from The Sub-Saharan Africa Survey of Heart Failure (THESUS-HF) here on June 5 at the World Heart Federation's World Congress of Cardiology & Cardiovascular Health 2016 (WCC 2016).

The results "add up to show that we need to do more in terms of education of our patients and of general practitioners," Dr Sani told heartwire from Medscape.

However, "the problem with anticoagulation in Africa is monitoring," he continued. Novel oral anticoagulants (NOACs), which don't require INR monitoring, are financially "out of reach." For example, in Nigeria, NOACs cost close to US$500 a month, but 70% of the population lives on less than US$2 a day, he said. Although warfarin is cheap, many physicians are reluctant to prescribe it, since patients often don't return for follow-up visits, putting them at risk of a bleed in the brain or elsewhere.

"If you look at all the new anticoagulant trials, the mean age is around 70," Dr Carlos Morillo (McMaster University, Hamilton, ON), who was not involved with this study, told heartwire . Patients in this cohort, however, had acute heart failure at 52, and many of the patients had AF and structural heart failure, which has a "huge impact," because these are young patients with a high risk of a debilitating stroke. This is "a population that definitely needs an important focus on treatment and prevention," he summarized.

Looking at 6-Month Outcomes in 1000 African AF Patients

THESUS-HF registry includes demographic and medical data from 1006 patients who had acute heart failure and were admitted to 12 university hospitals in nine countries from 2007 to 2010.

The current study aimed to investigate how having documented prior AF or AF detected on the admission ECG in these heart-failure patients was associated with all-cause death or readmission within 60 days and with all-cause death within 6 months.

The patients had a mean age of 52 years, so compared with patients in the West, "they are young, and they present very late, they are very symptomatic," Sani stressed. Half of the patients were women, and almost all (98.5%) were black. One in four had hypertension, and fewer had rheumatic heart disease (15%) or diabetes (15%).

Compared with patients without AF, the 20.8% of patients with AF were older (mean age 57 vs 51), more likely to be female (57% vs 49%), and had significantly lower systolic (125 vs 132 mm Hg) and diastolic (80 vs 85 mm Hg) blood pressures and a higher resting heart rate (109 vs 102 bpm).

Among the 209 AF patients, the 44% of patients with valvular HF were also younger (mean age 52 vs 61), with a lower mean systolic blood pressure (120 vs 128 mm Hg) and a higher LVEF (47% vs 38%) than patients with nonvalvular HF. Six in 10 patients with nonvalvular AF had hypertension.

Having valvular AF vs nonvalvular AF was not associated with length of the index hospitalization or rehospitalization or combined death or rehospitalization within 60 days. However, having valvular AF predicted an increased risk of death within 6 months (HR 2.11, 95% CI 1.05–4.24).

At 6 months, only 22% of patients with AF—33% of the patients with valvular AF and 12% of the patients with nonvalvular AF—were receiving warfarin, and about 60% of the patients with AF were on aspirin.

Large Global NOAC Trial in Rheumatic Valvular Heart Failure Launched

Study coauthor Prof Bongani Mayosi (University of Cape Town, South Africa) told heartwire that "until now, the only option we've had is warfarin or other vitamin-K antagonists, which are notorious for being difficult to use." Added to this, patients living in sub-Saharan Africa have to overcome "additional problems such as access to pills, access to INR testing, poor infrastructure in general—for example, when people have complications from warfarin use, they have difficulty getting into centers where they can be treated," he said, echoing the other experts. "So a simple-to-use and safer agent is needed," he said.

Prof Mayosi and colleagues recently published results of a pilot study, REMEDY[2], which included a look at warfarin vs rivaroxaban (Xarelto, Bayer/Janssen Pharmaceuticals) in patients with heart failure who had rheumatic valvular heart disease—who were excluded from the previous NOAC trials, which were done in the West, where such patients are uncommon, he added. However, rheumatic heart disease, which is caused by rheumatic fever after an untreated strep-throat infection, is common in children and young adults living in the developing world. The pilot study in 3343 patients from 12 African countries, India, and Yemen showed that treatment with this NOAC is feasible.

Building on this, at WCC 2016, Prof Mayosi and researchers from McMaster University announced the launch of the global Investigation of Rheumatic AF Treatment Using Vitamin-K Antagonists, Rivaroxaban, or Aspirin Studies (INVICTUS) program. They plan to recruit 20,000 patients with rheumatic valve disease and AF and conduct a noninferiority trial to see whether rivaroxaban is noninferior to vitamin-K antagonists to prevent stroke or systemic embolism, and a superiority trial to see whether rivaroxaban is superior to aspirin to prevent stroke or systemic embolism in high-risk patients. Recruitment is just beginning, and results are expected in 4 years.

It is important for clinicians in the West "to continue to collaborate with people in Third World, to know and understand their problems and in any way help them in terms of education, equipment, and ways to help the poor who are really very sick people who are in need of this and don't have access," Sani said.

Sani has no relevant financial relationships. THESUS-HF was supported by Momentum Research. The INVICTUS program is supported by a grant by Bayer and endorsed by the World Heart Federation. For more information about the INVICTUS trial, including how to participate, please contact Bongani Mayosi on bongani.mayosi@uct.ac.za or invictus@phri.ca.

For more from theheart.org, follow us on Twitter and Facebook.

Comments

3090D553-9492-4563-8681-AD288FA52ACE
Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as:

processing....