PhD Degree Awarded to Researcher Nawar Al-Wather in Cardiology

Researcher Nawar Ali Mohammed Al-Wather ‎was awarded a PhD degree in Cardiology ‎for her dissertation titled: The Predictive Value of D-Dimer Levels for Detecting Left Atrial Thrombus in Patients with Rheumatic Heart, which was submitted to the Department of Cardiology, Faculty of Medicine and Health Sciences – Sana’a University. The dissertation defense was held on Thursday, August 27, 2026.

The PhD Viva-Voce Committee, which was formed based on a resolution issued by the Graduate Studies and Scientific Research Council, consisted of the following:

Mohammed Mohammed Al-Kebsi – Sana’a University – Principal Supervisor and Committee Member.
Ahmed Lotf Al-Mutarrib – Sana’a University – Internal Examiner and Committee Chair.
Aziz Saleh Al-Zindani – Sana’a University – External Examiner and Committee Member.

The dissertation aimed to evaluate the diagnostic accuracy of the D-dimer blood test as an independent biomarker for ruling out left atrial thrombus in patients with severe rheumatic mitral stenosis, and to provide a rapid and safe medical alternative that could reduce the need for transesophageal echocardiography (TEE). This could help expedite clinical decision-making, particularly given the limited availability and high cost of TEE.

The study yielded several important findings, most notably identifying 360.6 ng/mL as the optimal cutoff value for ruling out thrombus, achieving 100% accuracy in the study sample. By contrast, the conventional clinical cutoff of 500 ng/mL was insufficient to rule out some cases, as it failed to detect 25% of active cases within the studied group.

The statistical models also demonstrated that D-dimer testing is a strong and independent biomarker, while other factors, including atrial fibrillation and mitral valve area, did not provide additional diagnostic value beyond that obtained from D-dimer testing alone.

Among patients whose results were not affected by anticoagulant medications, the study revealed a strong association between severe left atrial enlargement and elevated D-dimer levels. The mean left atrial diameter was 59.0 mm, reflecting the relationship between structural cardiac changes and the biological activity associated with thrombus formation.

The researcher recommended incorporating D-dimer testing into the routine assessment of patients with rheumatic heart disease before percutaneous transvenous mitral commissurotomy (PTMC) or electrical cardioversion. This would help identify low-risk patients and reduce the need to wait for TEE.

She also recommended using the study findings to guide the allocation of medical resources, particularly in resource-limited settings, by restricting TEE to higher-risk cases. This approach could help reduce financial and logistical burdens while expediting the provision of medical care.

The dissertation called for large-scale, multicenter future studies to validate the diagnostic cutoff of 360.6 ng/mL, assess its generalizability, and determine its potential incorporation into broader diagnostic protocols in countries where rheumatic heart disease remains prevalent.

According to the announcement made during the defense, this dissertation is the first study of its kind on this topic in the Republic of Yemen, representing a valuable research contribution to the diagnosis of thrombi associated with rheumatic heart disease.

The dissertation defense was attended by a number of academics, postgraduate students, researchers, as well as the researcher’s colleagues and family members.