The easily missed signs of the 'under-diagnosed' blood clot condition that caused Catherine O'Hara's death, revealed by a leading cardiologist - including a common mental condition and fingernail changes ⊖⊖

It's a condition that kills nearly 3,000 Britons every year. But according to Professor Rasha Al-Lamee, a cardiologist at Imperial College London , many patients are unaware of the early signs.