The aim of the study is to show the safety and efficacy of the SeQuent® Please (Drug Eluting Balloon or DEB) vs. commonly used Drug Eluting Stents in the treatment of small vessel disease and side branches by pressure wire guided percutaneous coronary intervention.

This study is a randomized, prospective, multi-center, efficacy study with a DES control group assessing the 6-month loss in FFR in patients treated with the "matrix coated paclitaxel-eluting PTCA-balloon catheter" SeQuent® Please and commonly used DES for small vessel de novo and side branch lesions. 100 patients will be studied in total with two equivalent treatment groups DEB & DES of 50 patients each.

Inclusion Criteria:

• Patients of at least 18 years of age.
• Patients with stable angina pectoris (CCS class 1-3) or with unstable angina pectoris (Braunwald class 1-2, A-C) or documented ischemia or with documented silent ischemia
• Patients must agree to undergo the angiographic 6-month and clinical follow-ups at 12 and 36 months.
• De novo coronary lesions including side branches in native coronary arteries (reference vessel between ≥ 2.0 and ≤ 3.0 mm, lesion length ≤ 25 mm as angiographically documented)
• Diameter stenosis pre procedure must be either ≥ 70 % or ≥ 50 % if ischemia corresponding to the target lesion is documented either by exercise stress ECG, stress echocardiography, scintigraphy, MRT, or suspected based on angina pectoris.
• Fractional Flow Reserve (FFR) must be less or equal to 0.75.

Exclusion Criteria:

• Patients with a life expectancy of less than 12 months
• Patients that were treated with one or more DES during the last 12 months which would not allow 3-month dual antiplatelet therapy if the patient were randomized in the DEB treatment group.
• Patients who are obliged to be on dual antiplatelet aggregation therapy for more than 3 months following study inclusion
• Patients with acute (< 24 h) or recent (48 hours) myocardial infarction
• Patients with severe congestive heart failure or with severe heart failure NYHA IV or with severe valvular heart disease
• Patients demonstrating clinical signs of cardiogenic shock at the time of the procedure (systolic blood pressure of less than 80 mmHg requiring inotropic support, IABP and/or fluid challenge)
• DES treated lesion(s) during the last 12 months.
• Thrombus burden (STEMI, NSTEMI) and/or total occlusion in the culprit segment
• In-segment stenosis of the native vessel within the 5 mm adjacent to the stent