Efficacy of Ambrisentan in Limited Scleroderma Patients in Improving Blood Flow to Hands or Feet

Inclusion Criteria: * Subjects should have limited scleroderma with disease duration \<7 years and should satisfy American College of Rheumatology criteria for diagnosis.9; * 10 Raynaud's phenomenon would be defined as episodic, bilateral, digital color changes (at least 2 out of 3 possible phases: * pallor, cyanosis, rubor), * provoked by cold or emotional stress. * Subjects should be between 18 and 70 years of age and be able to give informed consent. Exclusion Criteria: * (a) current tobacco users, * (b) advanced cardiopulmonary disease, * (c) clinically unstable patient, * (d) presence of active digital ulcers or prior history of digital ulcers which led to scarring or significant pitting of digits in the area of interest(presence of ulcers or pits would interfere with measurement of blood flow by LDPI), * (e) pregnancy (class X in pregnancy) or unable to use two reliable forms of contraception during the study if patient is of child bearing age, * (f) patients with moderate or severe hepatic impairment * (g) hemoglobin values less than 10% of the lower limit of normal per laboratory standards * (h) inability to discontinue vasodilator treatment including calcium channel blockers, nitrates, alpha blockers, PDE-5 inhibitors, ACE inhibitors and angiotensin receptor blockers at least one week prior to the study, * (i) echocardiographic evidence of pulmonary arterial hypertension \[estimated right ventricular systolic pressure \<35 mm Hg\], * (j) based on section 7.3 …