Expert retreat in clinical negligence claim not persuasive

Background

The case relates to the deceased’s mitral valve and whether treatment received in relation to its functioning was timely and adequate. The mitral valve is one of the four valves in the heart which prevent blood from flowing backwards as it moves through the heart. The mitral valve is located in the left side of the heart separating the atrium and ventricle.

Kennedys were instructed on behalf of the defendant.

By the time of trial, the claimant’s case was that the:

• Deceased ought to have been offered open heart surgery to replace a severely dysfunctional mitral valve in late 1999 or into the early 2000s, and that if she had had surgery, she would not have suffered from breathlessness for the remaining twenty years of her life.
• Deceased ought to have been commenced on treatment with anticoagulants in 1996 rather than March 1999 (admitted), and that if that had occurred, she would have avoided a transient mild stroke in July 1999. This was a very small issue at trial. The Judge considered the relevant literature showed the deceased was on balance fully anticoagulated by the time of her stroke and therefore the delay in administering anticoagulants for some three years was not relevant.

This was, however, quite some shift in the basis upon which the claim had been brought when proceedings were served. As Her Honour Judge Melissa Clarke observed at paragraph 12 of the judgment:

“In the Particulars of Claim the Claimant alleges fifty breaches of duty on eleven occasions over a period of twenty-five years, from 1991 to 2016.”

At paragraph 13 the Judge stated that “The Claimant’s expert cardiologist in his breach of duty and causation report identified fifteen breaches of duty by the Defendant…”. Having set those out, the Judge at paragraph 14 then observed as follows that:

“By the time of trial, however the issues had narrowed very considerably. The Claimant’s expert had resiled from all [but two] of the above listed breaches of duty….”

Whilst the claim would otherwise have been statute barred, the claimant relied upon a secondary limitation argument based upon her date of knowledge, which was 2016.

Decision

The court heard evidence from two expert cardiologists instructed on behalf of the claimant and defendant respectively.

The Cardiologist instructed on behalf of the claimant sought to demonstrate the clinical picture in November 1999 as evidenced by the heart catheterisation procedure:

1. Showed the deceased’s pulmonary artery (PA) pressure was significantly raised;
2. Showed the existence of pulmonary hypertension arising from mitral regurgitation and severe mitral stenosis; and
3. Enabled the expert to produce an estimated pressure gradient across the mitral valve of 10mmHg.

Accordingly, the opinion of the expert instructed on behalf of the claimant, was that these observations showed that the deceased had more advanced, more severe mitral valve disease then the treating clinicians had appreciated and but for this failure she would have undergone a mitral valve replacement improving her quality of life.

The Judge observed (at paragraph 75 (vi)) that “it became apparent in cross-examination” that the Cardiologist instructed on behalf of the defendant “did not compare two simultaneous readings of the pressures he was comparing” to establish the pressure gradient he sought to suggest existed.

At paragraph 75 (xi), the Judge observed that the pressure gradient across the deceased’s mitral valve at the time of catheterisation could have been more than the claimant’s expert had estimated, “or it could have been less, or it could have been zero” and as such the exercise the claimant’s expert had carried out was “no better than pure speculation”.

The Judge added (at paragraph 75 (xix)) there are “a number of possible explanations” for the deceased’s “elevated PA pressure during the catheterisation”, and accepted “that more than one factor may be at play.” Clarke J stated:

“Those explanations are: (i) systemic hypertension; (ii) hypertension caused by anxiety/pain relating to the procedure itself; (iii) high pressure in the LV causing an increase in PA pressure; and (iv) severe mixed mitral valve disease.”

Clarke J also held that looking at the entirety of the measurements of the mitral valve area over the years, the deceased did not have a severe mitral stenosis until 2016.

In addition, even had there been follow up after the heart catheterisation in 1999, there were no circumstances present what would have led to a mitral valve replacement surgery at any time prior to 2004 as pleaded by the claimant.

Comment

Where an expert, instructed on behalf of a claimant or defendant, has such a fluctuation in their opinion, such evidence needs to be appropriately tested. The decision in Bolitho places emphasis on lawyers as the final arbiters – engaging in the exercise of testing the evidence is necessary so as to form a reasonable view of the merits of each case.