In this observaltional study, 90 patients aged >12 years old with T1DM who are on MiniMed 780G system will be included.We aim to investigate the association between time in range (70-140mg/dl) and time in tight range (70-180mg/dl) with markers of endothelial and cardiovascular function.

In this observational study, 90 participants with T1D on MiniMed 780G system will be included. HbA1c, anthropometric measurements, CGM and Insulin Metrics will be assessed in all patients. Moreover, the investigators will assess:

1. the pulse wave velocity, the augmentation index and the central systolic blood pressure which are markers of arterial stiffness
2. the perfused boundary region of subglingulal vessels which is marker of endothelial function
3. the global longitudinal strain which is marker of myocardial function.

Inclusion Criteria:

1. Clinical diagnosis of type 1 diabetes >1 year prior to consent date. Diagnosis of type 1 diabetes is based on the investigator's judgment; C peptide level and antibody determinations are not required.
2. HbA1c < 12.5%
3. Age >7years at the initiation of the system
4. Multiple Daily Injections (Basal Bolus therapy) with Total daily insulin use of great than 8.0 units per day over a 1-week period
5. Clinically able to start the AHCL system
6. History of 3 clinic visits in the last year

Exclusion Criteria:

1. Diabetic Ketoacidosis in the 6 months prior to screening visits

patients aged >12 years old with T1DM who are on MiniMed 780G system .